There is a scan knocking around on the net from the official Xbox 360 magazine review, which gave it 10/10. Official console mags usually aren't the best source of unbiased reviews but I'm inclined to think it's pretty much on the money with PCG UK giving it 95% too, they do have unbiased reviews and are pretty reliable (apart from that one time with their Deus ex 2 review).
It looks like there is going to be an 360 demo according to this page
The Rapture Gazette - The Bioshock blog , lets hope we get a PC demo too.
I've only got a couple of reservations about the game, one is the online activation, I just hope they don't still expect me to have the disc in all the time as well. The other is that they are adding some extra content exclusive to the Xbox version
