Probably everyone remembers the hype around Nether-Go when Invasion came out... And how soon it was forgotten and pushed into tier 2 category.
I liked the basic idea behind the deck from the very beginning, and continued to experiment with it. (I didn't have any other choice... What would I have done with my four foil Undermines?) My first versions shared the same mistake that I see in the netdeck versions today: They tried to be pure control decks. Draw-Go isn't the best alternative when you cannot use Powder Keg or Masticore. The original concept was to combine superior card drawing with as few dead cards as possible; Nether Spirit was the only nonland permanent used, so that the opposing player's removal spells were virtually useless... To avoid dead cards, the deck contained four Recoils as its only creature removal.
The flaw in this thinking was that almost every deck plays with creatures, and most of them with lots of them! The only way of stopping rebels was if you managed to Foil their first searcher, and Fires basically walked over the deck. Black has the best spot removal in Type 2 and Nether-Go wasn't using it. Nowadays I use two different removal spells in my deck: One of them is, naturally, Vendetta. It can kill early searchers, elves, and mana birds, thus slowing down Rebels and Fires enough for counterspells to kick in. I chose it over Terror and Snuff Out because Terror can't kill Chimeric Idols, and my version of Nether-Go only has four basic swamps, so the alternate casting cost of Snuff Out would have been useless... The other spell was Tsabo's Decree. At first I had only one in main deck, to combat Rebels in game one, but soon I noticed that it was good against almost everything else, too. Blastoderm's untargetability wasn't a problem for it, Jeweled Spirit couldn't be protected against it, and it could also handle Kavu Chameleons. The high casting cost isn't as big a problem as someone might think. It is an instant and can be cast during your opponent's end step, so you're not taking very big risks by tapping your counter mana...
Now that I have gone through the most fundamental changes, the decklist might be in order:
Nether-Go, version 2:
4x Accumulated Knowledge
4x Fact or Fiction
3x Tsabo's Web
3x Tsabo's Decree
3x Nether Spirit
4x Underground River
4x Salt Marsh
1x Tsabo's Decree
4x Dread of Night
Some card-by-card analysis might be in order - at least in those cases where my choices differ from the traditional Nether-Go:
4x Counterspell, 4x Undermine, 2x Foil
Usually these decks have more counterspells than this. With the presence of good creature removal, the need for counterspells has decreased. Undermines and Counterspells are non-negotiable. I have to admit that loss of three life would look better in a more aggressive deck, but the low cost of only three mana for an unconditional counterspell makes Undermines the superior choice. (If someone finds a way to support Dromar's Charm, I'm listening...) Foils, however, aren't really great against anything and are often sideboarded out... They still have their role in the deck, though; since they are unconditional counterspells, they are not terribly bad against anything either, and the alternatives aren't very good. Power Sink is bad against control decks, because it's nearly dead in counterspell wars, Spite/Malice is just as expensive and doesn't have ACC, and ten islands can't support Thwart. Memory Lapse would better suit a deck with a capability for beatdown.
4x Opt, 4x Accumulated Knowledge, 4x Fact or Fiction, 1x Recall, 3x Tsabo's Web
An important thing is to remember to never sideboard out any of the first twelve cards listed here: Opt, AK, and FoF. One exception is when your opponent also plays with the Knowledges; then it's often wise to side a couple out... Recall is mostly an endgame finisher. It often helps you mostly when you have already won and just seals your victory, but that kind of card has its merits in tournaments with fifty-minute rounds. It can also pull you out of the dread "two-Spirits-in-grave" lock. Sometimes you can also let some permanents, like multiple Story Circles, get into play during the early game, knowing that you can use your two Recoils twice when you have achieved control. Recall can usually be sided out in matchups where surviving the early game means everything, such as Fires or Rebels.
Tsabo's Webs are good enough reasons to ignore the "no Disenchant targets"-rule. This deck runs very little land for a control deck, and without the Webs an opponent with two or three Ports could easily force through whatever he wants... You know when to side these out...
2x Recoil, 4x Vendetta, 3x Tsabo's Decree
There's no real need for four Recoils now that the deck has some real creature removal. Even the last two can be often sided out in creature rush-based matchups, as they are only there to combat bad artifacts and enchantments. Blue Skies is an exception: It tends to play so many acc Thwarts and Gushes that Recoils are almost good as removal against it.
3x Nether Spirit
Three seems to be about the right number. You can often side one out in control-based matchups...
4x Swamp, 4x Underground River, 4x Salt Marsh, 10x Island
22 lands might sound like too little, but there are fifteen one- and two-mana card drawers in the deck. Even one blue producing land and an Opt is an okay starting hand if you're not going first.
You really can't lose. If you can get an early Nether Spirit out, you should probably save Vendettas for Chimeric Idols. The Rebel chain just can't do anything to three maindecked Tsabo's Decrees. The only risk in this matchup is that if you cannot find an early Tsabo's Web, the rebel player might stop you from getting to six mana, either by Bowling your lands or by forcing through an Armageddon with Ports. Oh, and remember that Longbow Archers are Soldiers - not Archers like they used to be in Visions. Sideboard in 4 Dread of Nights and the last Tsabo's Decree and take out 2 Foils, Recall, and 2 Recoils.
Fires (and the Kibleresque variants too...):
Fires is a good matchup, but sometimes it gets such a speedy start that you just get overrun. This matchup is all about early survival. If you have many counterspells and the Fires player is going first, you should probably Vendetta their first mana bird or elf. Otherwise, save your Vendettas for Chimeric Idols and River Boas. There are some tricks to gain card advantage against Fires: First is to never counter Fires of Yavimaya. You have to deal with every one of their creatures anyway, and all your answers are instants, so the haste means nothing. The other is to not counter Blastoderms when you have an active Spirit. Three or four turns of chumping and you have traded zero cards to one of their heaviest creatures! Don't try this if you're at low life or if your opponent is running Urza's Rages...
Sideboard in 1 Perish, 1 Tsabo's Decree, 2 Misdirections if they are running Urza's Rages - or much other burn and as many Meekstones as you have room for after possible Misdirections. Side out Recall, 2 Recoils and 2 Foils.
This isn't a very good matchup. Twelve of their creatures ignore the Nether Spirit, and sometimes they can counter unbelievable amounts of spells. A big key to this machup is the order in which you try to cast your removal spells. If they haven't signaled lack of counterspells, you should try to cast Vendettas first, as the loss of life is part of the effect and doesn't happen if the spell gets countered. If they Thwart or Gush with the alternate casting cost, your Recoils suddenly become real removal spells as your opponent lacks the mana to cast things back. The best thing is when you get to Tsabo's Decree Troublesome Spirits away when your opponent has just gotten to four mana. You need to attack aggressively, because this matchup is more about damage race than getting control. Modern Blue Skies decks have too much counterspells and card drawing for this deck to fully control. After sideboarding, it's all about Meekstone. Spiketail Hatchling is their only flying creature that untaps under it.
Sideboard in 2 Misdirections and 3 Meekstones. Side out 3 Tsabo's Webs, 1 Recall and 1 Tsabo's Decree.
This is just as good matchup as normal Rebels, but more difficult to play well against. You have basically two routes to go in this matchup, and you have to choose between them based on what the early game looks like. First route is to kill or counter all their searchers. If you manage to do this, their only card drawing spell, Brainstorm, becomes virtually dead. As your card drawing works normally, you can usually outcontrol and outcounter them. The second route is to let them do all the early searching they want. Then you must counter their Brainstorms and win a counter war over a Tsabo's Decree. You often need two Decrees for this; one during your opponent's end step and one during your turn. Sometimes you can also get the Decree through in response to your opponent's searching. If you manage in this, all your opponents creatures will be dead cards, as their number is irrelevant to the important thing: Resolving Tsabo's Decree. Counter-Rebels have fewer counterspells than one would think, and you can get Tsabo's Decree to resolve more easily than one might expect.
Sideboard in 4 Dread of Nights, 2 Misdirections and 1 Tsabo's Decree. Take out 3 Tsabo's Webs, 1 Recall and 1 Foil.
You're likely to win first game because of many dead cards in UW-Control... But after sideboarding it gets much worse. You have about equal amounts of countermagic and card drawing, but your opponent has Disenchants and more real threats than you: three or four Millstones and Disrupting Scepters as opposed to your two Millstones. You can win via a lucky Lobotomy or by drawing much better than your opponent, but it's not likely. The situation is entirely different if your opponent still tries to pummel you to death with Angels after sideboarding; then you're on top.
Sideboard in 2 Millstones, 2 Lobotomies and 2 Misdirections. Take out 2 Tsabos Web's, 1 Accumulated Knowledge and 3 Vendettas.
Void / Black Red Recursion / Discard
Nether-Go really doesn't like first- or second-turn black creatures that force discards. (Even if it's a Spirit? - The Ferrett) However, if that doesn't happen, these matchups are pretty winnable. Recurring Hammer of Bogardan or Pyre Zombie are, of course, bad, but with an early Nether Spirit and some Undermines you can most of the time turn these games into a winning damage race. These decks have to run pretty mana-intensive spells, so you should usually have enough counterspells. Your sideboarding decisions have to reflect your opponent's deck. Misdirections are often good, and Lobotomies help against recurring things. A fourth Tsabo's Decree also often helps. You can usually side out Foils, and Vendettas too if your opponent is not using Chimeric Idols.
Unfortunately, I have no experience of playing against traditional Nether-Go. I hope that most of this applies to that too. The key to winning the first game is to draw as few cards as possible. The player who first finds his second Nether Spirit usually loses, because he becomes vulnerable to Tsabo's Decree. Card advantage means nothing, because there are so few spells that really matter. Both players always have enough counterspells, and amount of mana is the limiting factor, and Tsabo's Decree during one players end step and one during the next turn usually causes one to resolve. After sideboarding, the player who gets Millstone out wins. Sideboard in 2 Millstones, 2 Misdirections, 1 Tsabo's Decree and 2 Lobotomies. Side out 4 Vendettas, 1 Nether Spirit, 1 Accumulated Knowledge and 1 Tsabo's Web.
The next matchups are pretty marginal and I will only cover them briefly.
A favorable matchup. You have to play as beatdown deck. Don't hesitate to Vendetta Glacial Walls and like, because your life means nothing in this machup.
B/U Fish and Mercenaries
These are very bad machups. Quick creature swarms backed up by counterspells or unaffected by Vendettas are almost impossible to survive.
What about 7th Edition? If the spoilers are correct, the deck doesn't lose anything besides its lonely Perish and Recall. Return of Duress is much bigger news. Duress in itself shouldn't be too bad, but if B/U Fish and black/red decks rise in popularity because of its return, that's bad news. Armageddon is leaving, and that's nice, because it was almost only meaningful spell that Rebels or Red Zone players could force through when Tsabo's Web didn't show up.
It is of course true that you cannot expect to win with decks without knowing how to play them, but this is especially true with Nether-Go deck. Many decks can be played in almost same way in all machups, or in the same way against all control decks and in some other way against beatdown decks. This is not true with Nether-Go. You have to consider every machup separately and find the weak points in those decks, how to survive and how to generate most card advantage. And you have to keep your eyes open for small things. For example, it's not always wise to wait for your opponent to end his turn before casting Fact or Fiction. Sometimes you should cast it during his attack before blocking anything, so that he cannot force you to take the pile with lone Nether Spirit if one should show up...
I have won seven small tournaments (twenty to thirty players) in row with this deck, and I think that this archetype shouldn't be buried just yet. I'm not telling you that the Nether-Go is somehow "the Best Deck" either, but it's definitely tier one, and it's also a great tool to outplay worse players.
Thank you for your time,