My mom and I saw it this morning, and I really enjoyed it. I'm not overly familiar with the Forgotten Realms world, I've never played D&D but I have read one of the RA Salvatore Drizzt novels.
So coming at this as more of just a general fantasy fan, I thought it was a lot of fun. Most of the humor worked pretty well, and I thought they did a good job of putting it in when it felt appropriate, and then being more serious when they needed to. I'm not sure accurate to the game they were, but I thought it had some really cool creatures, and most of the effects used to make them were pretty good.
It had some pretty cool action sequences, which was especially impressive since this was the first big action movie like this that the Daley/Goldstein duo have ever directed.
There is one thing I do remember from the book I read, The Legacy, that I wanted to ask about. Was that Menzoberranzan that they showed when Edgin & Co. were in the Underdark?