Yeah, I got to play it -- It's awesome. THQ was really nice and flew me out there to check out the game. Got to play about 2 hours of single player and about 4 hours of Multiplayer. It's not a Gears clone, it's SOOOO much more.
If you haven't pre-ordered it, you might want to look into that, if for nothing else, than the freaking customizer. ALL of the GW colors were there and it's very robust. OH and the game play is addictive and fast pace. I'll be playing it on Xbox 360 and I look forward to mauling all of your faces at some point.
Game modes at Launch: Single Player, Multiplayer (8v8).
Coming Soon(TM) -- CO-OP! they didn't release any other details for CO-OP(that I can post) but it is coming after launch.