Originally Posted by Ob Freely
I don't really see this as much of a debate. Thoughtseize is a fantastic card in nearly every matchup. Dark Confidant is a fantastic card in several matchups, but is a pretty terrible card in several matchups, as well.
The bottom line is that I don't even consider playing Threshold without Thoughtseize, anymore, unless I really want to play Blood Moons. That single card has completely obviated all of the old UGw and UGr lists, and you could never say that about Dark Confidant.