First blush - nice hardware, definitely responsive as hell. I'm having a very hard time getting used to it. (This is definitely going to effect my WTB performance tomorrow, I think.)
The one thing that has me on the edge about whether this is a keeper or not is the thumb buttons. They are so stiff that it actually requires real effort to push them. It's not something you can just key without having to think about it. If I try to hit the button to talk in vent while I'm trying to snipe, it's completely disruptive. It either ends up throwing my aim way out of whack, or requires me to stop any precise movement.