Great style. Great voice acting. Far too much like System Shock 2, and not as good.
Bioshock does not maintain the replayability of System Shock however. Unlike System Shock 2 you do not have to spend points into various weapon skills, instead you get them and then you can immediately use them to their best effect (save for no-skill weapon upgrades). So whereas System Shock 2 forced you to choose between mental, physical and engineering powers, Bioshock does not. Spending your ADAM one way or the other will not effect how you play the game by much. This is a missed opportunity and very unfortunate.
On the upside, Bioshock has superb artwork and voice acting. The world around you is extremely colorful and lifelike. There is a lot to see and the story is interesting enough for you to want to see it through.
If you haven't played System Shock before, this game will be great for you, otherwise it's just good.