The release in Europe is slated to be the 24th of Novemeber; quite likely pushed back so as not to clash with the Gears of War release.
At the moment there is a Pre E3 demo on Xbox Live weighing in around 340mb. I managed to give it a whirl yesterday and I quite liked the game it was fun but the camera is simply one of the worst I have encountered, accompanied by some major control issues (especially the homing attack) which I can only hope are resolved towards the release. The graphics are nice but like what I'd expect from a Sonic game on a next gen system; as for the music the demo doesn't offer much but the tracks I've heard are quite enjoyable.
All in all I think I may pick this up come the 24th, I haven't played a Sonic game since my Megadrive days, oh the nostalgia.
Trailer Link
Jam it back in, in the dark.