The second film is packed with action (lots of it), humour, great characters, and even some romance. Martin Freeman's Bilbo is as adorable as ever, and Kili and Legolas are still hot, as is Tauriel (an OC elf). Fabulous, fun stuff, and I'm looking forward to a second viewing in 3D with imhilien. There's even (briefly) a cute black cat and two pug dogs, the dogs apparently belonging to Peter Jackson.
I was thinking afterwards that I rather missed the development of Bilbo's character and relationships we saw in the first film, but there's a scene in Mirkwood that shows some further changes in him.
The first film was pretty faithful to the book, but this deviates quite a bit - and I didn't mind at all. It's an exciting ride (in barrels and other conveyances) and ends on a huge cliff-hanger which has me asking why, why, why do we have to wait another whole year?
There's an excellent review here with a big spoiler space with repeated warnings so that people who haven't seen it have every chance to bail after the first bit.
Also posted on Dreamwidth, with comments.