I ran Landorus/Mewtwo/Garbodor at my regionals, and, well, I finished 4-4. Hear me out, though, I still think the deck is great in this meta. The first round I destroyed a Darkrai/Hydreigon that ended up doing better than I did, and round 2 I downright won the Mewtwo war against a deck that I would have normally had a bad matchup against (the guy made top cut.) Round 3 I barely lost to RayEels, since he was luckier and faster in setting up his Eels (he got 3 out) while I dead drew in terms of setting up Garbodor so he killed off my Trubbish. Not to mention, I would have donked his Tynamo if I went first. Round 4 I started a lone Trubbish and their Mewtwo donked it. To be honest, I find that donk possibility to be the deck's biggest flaw, but if it doesn't stop people from playing Eels, then it shouldn't stop them from playing Garbodor. Round 5 I lost to the bad matchup you have been talking about, being Landorus/Tornadus. It didn't help that the guy ran a Gold Potion and 4 Potion and he hit all of them. Round 6 and 7 I beat another Darkrai/Hydreigon and a deck with Giratina, Sigilyph and other EXs. Last round I lost to another deck of EXs, for several reasons including: a possible misplay on my part, I max potioned my Garbodor at 30 damage when I should have saved it, and more importantly, he got heads on Sableye's confuse ray. That, I call lucksacking....
That's pretty much how my day went with the deck. Call me bad, call the deck bad, but I think that if built right and played right it has great potential and the only deck it will really lose to consistently is a deck with the same non-ability attackers minus the Garbodor. I should also mention that I only went first ONCE that day, round 2 to be exact.
The deck should have a good matchup against Darkrai variants in general (assuming you have Landorus and/or Terrakion), Eels (Rayquaza is harder, but you should win unless you whiff and get Garbodor too late), Blastoise variants (though sadly I never played one at Regionals) and Sigilyph-focused decks. Even the matchup against the big EXs without abilities is very winnable, despite a bit less consistency. The Garbodor, Trubbish and Rescue Scarves can be used as fodder for Ultra Ball and Computer Search, and as long as you outplay them in a Mewtwo war (seriously, it's stupid NOT to play mewtwo in any deck, especially Garbodor) and don't get totally screwed with your hands you can win it.
Obviously, Garbodor is and always will be a very tricky and gimmicky deck, but it's better than usually given credit for. It plays off of the format, and Plasma Storm may make it more or less viable. But as these regionals records have shown us (see Mudkip711's post), this deck is a force to be reckoned with in the format.