I saw the first one and actively disliked a lot of it. So much so, that I skipped the second one.
I won’t give any spoilers, which is a weird concern in a book that has been out for so long. I liked this one, to the point I will watch it again outside a theater (this was the first time I’ve been in a theater since Hobbit the First came out). The shot that killed the dragon was a bit silly, but there weren’t many other moments that made me check my watch like in the first one. There were one or two scenes that were probably shot for their 3D potential, but they weren’t distracting in 2D.
Overall, worth the time and trouble to see in the theater. Heck I may even watch Hobbit the Second on DVD now.