I saw Thor: The Dark World a week ago, but got pretty busy doing other things so I didn't get around to reviewing it until just now.
Short version? Satisfying and fun. It clears my Threshold of Awesome on the strength of Tom Hiddleston and a very entertaining climactic battle. Most superhero movies seem to assume that we just want flying and punching and destruction at the end. Me, I like there to be some story and some tension in the fight. Also, something new. Thor 2 delivered that for me.
If you enjoyed Marvel's first Avengers-era Thor installment I'm confident that you'll enjoy this one. It is better! And the reverse may be true: I found that after watching this one I enjoyed the first Thor film quite a bit more (my daughter insisted we watch it after she came home from seeing The Dark World with Sandra.)
The film's biggest weakness is the prologue. I love watching a story unfold, and learning secrets of the past as the characters learn them. This prologue was unecessary, and robbed the film of some tension. There are good prologues, of course, but this wasn't one of them. Fortunately, the film overcame my scowl of deep disdain fairly early on.
Be sure to stick around for the very end-most credits. There's the usual Marvel teaser following the dressed-up credits (is there a name for those?) and then after the long black-and-white scroll we get another couple of goodies.
Thor: The Dark World comes in at #8 for me, just ahead of Pacific Rim.