This thread kind of took a detour into bad Classic Stern land. Viper is terrible and IM also blows, although it admittedly looks awesome. At least nobody brought up Catacomb!
I don't think you can compare any of those games to quicksilver, which is completely awesome to play. Just rips. I'd love to have one in New York City to play, so somebody please hook up the OP with the machine he seeks.
I've sold him a game, and others here have too. All will agree he's a breeze to deal with, knows what he wants, and sale or no there's not going to be any bullshit at all.