Not as good as the first. Since sequels practically never are, I wasn't disappointed. I like the characters from the first movie, and I enjoyed seeing them again.
Swords and ray guns are just a lousy visual mix. I could willingly suspend disbelief, but a decent design would have left more energy to willingly suspend disbelief for the plot. The discovery that nudity improves thinking to the point that Selvig's
tech is so useful is quite a strain. Perhaps if Jane Foster had stripped down to her underwear too Thor wouldn't have been needed at all.
Lots of ill-motivated hugger mugger and to-ing and fro-ing weakened Thor's dramatic choice which rather came out of the blue. Even more confusing, if a mortal lifetime is such a nothing, Thor taking a vacation with Jane is also a nothing.