Not ready for release at all. The game was rushed to make the holiday deadline and it shows with lots of framerate bugs.
The other issue is that it's much harder to aim using the Xbox controller. Especially when playing some of the vehicle missions. Levels I thought where easy on the PC became tough as the framerate would drop and it was hard to target the enemy fast enough. It's a good thing you can't hurt your teammates as I kept shooting them in the head as I wasn't able to aim precisely enough all the time to hit the Strogg as my teamates ran in front of me.
Anyway, to sum up the game, I'd recommend passing on this one and getting the PC version. Raven and ID software obviously rushed this port of the game out, and at the last minute tried to fix the framerate by putting in low-res textures and changing the shadows in the game. Even doing this it didn't help the framerate much. It's funny when you consider that Doom 3 looks pretty good on the original Xbox. You'd think that if they got Doom 3 working on that older system, with this brand new next-gen console they could get Quake 4 working better. Oh well, at least there's Perfect Dark and Call of Duty 2 to play instead.