I love this game. The story and character development are the main reasons(I love Elizabeth), but I also think it has the best ending in any videogame I have ever played. It is fanatastic. The vigors are fun (The only ones I used with any frequency were Bucking bronco and shock jockey) the guns were alright but nothing groundbreaking. But all in all I highly recommend this game.
And for all you people saying it shouldn't be called Bioshock, all I can say to you is complete the game. Then you'll realise how apt the title is, Especially the word "Infinite".