Some people have a lukewarm response to the combat, but I think the creative use of Plasmids and the sheer viciousness of the splicers - particularly later variants tooled up with Plasmids of their own - makes up for the lack of what you might call advanced collaborative AI.
To be honest, if you can play Bioshock and you choose not to, then you're as mad as the nuttiest splicer Rapture holds. Have your head examined before it's too late. On the 360 it's a no-brainer, and on a moderately specified PC - in one case an Athlon X2 3800 with an ageing Radeon X1800 GPU - a few detail concessions result in a smooth and still stunning experience. I was lucky enough to try it on a Quad Core system with an Asus GeForce 8800GTX, and it's easily the best thing that I've ever seen.
Yet at risk of reiterating a point, it's not the technology that matters here, but the fiction. Moments of Bioshock will haunt me for months to come, and I don't believe for a second that I can resist Rapture's lure and not return. Only time will tell where Bioshock sits in the pantheon of all-time greats, but if you buy one game this month, this year - let's be clear, this whole decade - this is the one you shouldn't miss.
The finest game of the current generation. Other games may match or surpass it on technology or features, but it's hard to imagine anything competing in terms of storytelling prowess or overall vision. A masterpiece!