Well, working from my list that I posted earlier, my results have been as follows:
(If I haven't played the match-up. I'll guess how it'll play out, but no more)
vs LostGar: Currently 6-0 in real tournies, and 4-1 in testing. Don't run any silly extra tech lines, run the full spiritomb count and just start OHKOing with powerclaw on turn 2-3. Use mesprits and seeker to shut down uxie/smeargle/trick reveal at opportune moments and coast to an easy win. However, too many tech lines will make you have cards clogging up your hand and make it so that hurl will usually hit even without a seeker. If you run the straight T-Tar, piece of cake.
vs VileGar: The best counter to a spiritomb is always a spiritomb. This is the only really matchup umbreon shines, but I feel it isn't even necessary. Use mesprits in the early game and late game use the seekers to heal tyranitars and refresh a trainer heavy hand. Use bebe's smart and never put the 2nd dark on a tyranitar except to kill a vileplume if it somehow ends up active. As long as you don't waste energy and they don't constantly flip heads for fainting spell, this one should definitely be in your favor.
vs LuxChomp: This is a bit of a point of contention for the deck. I've heard both sides of the equation say that they have the advantage in this matchup. I believe this is biased enough that I wont commit to anything past 'even'. I'd say a lot more lower quality players will play Tyranitar over LuxChomp(difficulty to play optimally, cost etc.) and this can make luxchomp players feel it better in their favour. So far, in my testing (with quality players, but not normally luxchomp players), putting prevalence on getting a spiritomb active and using Mesprits as quick as possible to slow down the game until turn 4-5 really really turns it into a much easier game. Just set up a couple of tyranitars behind spiritomb (uxie cant get sprayed) and go to town OHKOing. Not claiming this is easy in any way, but I have had better than 50/50 results.
vs Jumpluff: Is this still a deck? Weird. Get a spiritomb active and build up a couple of tyranitars (have another spiritomb on bench in case of regice) If they don't, just drop you uxie there. Have no problems SSUing or seekering just to take less damage. Once you have a tyranitar set up, you hit for 90+ for the OHKO, while they hit for... 100-120 tops. This isn't a race they should win.
vs Machamp: If they have any sort of setup, concede. No worries, you probably shouldn't play more than 1 in a tournament anyway. Techs you may have are generally too slow to matter anyway. Still have yet to play in tournament.
vs Gyarados: Never actually played this matchup. I feel that mesprit makes it a little better (shuts down regice/azelf early) as late game you can get OHKO's while they can't. The only worry is they have a much better recovery than you. The best bet is having 2 set up and alternating with SSU and seeker. I can't see this being anything but slighty below even.
vs Donk decks: Spiritomb/mesprit. Showuld be quite easy as long as you don't get an awful start and go first. Played a handful of games, haven't lost yet.
Vs Random decks(general): This sort of deck has proven itself to have little problem with random rogue decks as it can stall than one shot pretty much any pokemon in the format.
