I think that BioShock 2 is better than BioShock.
BioShock had nice themes and an interesting backstory, but that doesn't carry a game. It's terribly paced (worse than even Rockstar have managed, in places) and the story only turns up for the twist.
The biggest crime of the pacing comes with the twist too - it spends all that time building up to it, and then, when you reach the office door, what happens? Oh right, you're sent off for another hour to perform the bloody "blue key for the blue door" task that you've already done several times over.
I also felt that the twist failed, because they revolve it around a character that is not a character. I am a big defender on silent protagonists, but they should have looked at Half-Life. The whole thing going on between Gordon and the G-Man? That's interesting because of the G-Man, NOT Gordon! Same goes for Alyx; I care about what happens to her because she feels like a real person, I don't care how Gordon feels because he's meant to be the place-holder for me. So trying to attribute any big reveal to HIS personality alone doesn't work.
BioShock 2 gave me someone to give a crap about. Alright, they totally fucked up the moral choice system like it they did in the first, but up until the end it was quite interesting, because they made an attachment to a character that grew on me as well.
So yeah, that's mine.