The show is completely changed around, turned upside down, shaken up, and turned right again. There are some big changes, but not many. The cast set-up is the same, the hierarchy within the cast is also the same. How the story is played is completely different than the first season, and that isn't necessarily a bad thing! The opening and ending got a little monotonous, but not too bad; it fit the episodes and the meaning of the show in its entirety.
I wish it was a little bit closer to the first season, but I like that it's taken it's own route to be different and yet the same. Absolutely a fantastic second season!