Smutko: Did you consider boarding out the topdeck tutors? I've heard of people boarding out Mystical especially and Vamp far before they would some of the accelerants because they are also -cards. At least Mana Crypt and Mana Vault stick around after you use them.
For the decklist as i ran it at that tournament, I didn't have much I felt like bringing in, so there were only so many cards I was going to take out. Had I more cards for the mirror, I may have decided differently, but at the time my logic was thus:
Regarding vault: as far as I'm concerned, this doesn't stick around after you cast it, but is a colorless dark rit unless you've got a key. I'd often prefer to skip a draw to potentially tutor up the win than pay 4 on my upkeep to untap my artifact.
Regarding crypt: my impression of this card is that it's useful for a quick ramping in the early game. If you don't have any immediate use for the mana, so you hold on to it, or if there a bunch of turns after you cast it, it gets pretty bad.
Regarding the tutors: the deck has three game winning combos: tinker + counterspells, tez + counterspells, key + vault + counterspells. The tutors help you put those combos together, and once you do that, the game is over, and it doesn't matter how many cards you spent to do it. How does this jive with treating the matchup as a regular control mirror? Because the more mana you have, the more counters you can cast in a turn, and the more likely you are to win a counter war. Having more mana also lets you not tap out when you cast your scroll, tfks and the like, so you're more likely to cast them rather than just sitting back on untapped blue mana, and your opponent is more likely to let them resolve in the face of your untapped blue mana.
Additionally, tutors can act as pseudo duresses. If you don't know what's in your opponent's hand, and they cast a tutor to your one counter in hand, you're put in a tough position. If they already have a game winner in hand, they could be getting the force to push it through, and you lose if the tutor resolves. If they already have a counter in hand, they can get the game winner, and you lose if the tutor resolves. If you think they already have a counter or a game winning card, you're pretty much forced to counter the tutor and bluff further counters in hand. Essentially, the tutor just duressed your counter. Being able to put opponents in that situation, especially if you win when the tutor resolves, is good enough to spend a card if it resolves.
Lastly, having the tutors makes for strong gifts without losing your good cards.
