Troika. You're talking to this forum's leading Troika fanboy. If you read my rants defending ToEE and Arcanum on the ol' Troika Board, you'd understand.
Without trying to get too long winded, I'll give some reasons. First off, for obvious reasons, it's got Tim Cain, Leon Boyarsky, and Jason Anderson, the "three leading principals" of their past games. Then they've got experience in the industry. And, if Vampires does well, they'll also have a bigger budget than what was scene in Arcanum and ToEE.
I haven't seen much of Silver Style's work. I'll reserve judgment until I've played The Fall.