I adored the first Bioshock. I found it unique, fun, and the story-line was epic. The second one, not so much.
I hated playing as a big daddy. I found it annoying, the traps were aggravating and the story line, although interesting, wasn't what I wanted. However, I did greatly enjoy the part where you saw through the eyes of a little sister (it was my favorite) and the ending was much better than the first.