Saw it last night as part of a double feature with Wrath of Khan.
Great film overall! The cast dynamic was excellent and Cumberbatch managed to steal the show in several places which is high praise when you consider how strong this new cast is.
The plot moved at a lightning pace but yet there was still time for some character development. There was also some nice continuity in terms of several references to the first film of this new timeline. This film relies more on knowledge of the Trek franchise than its predecessor but not to the point where it will alienate more casual audiences. I will say this-- it was very interesting seeing this film right after WoK. VERY interesting.
My biggest complaint is that I'll not get a TV series with this set of actors. The wait for the next film is going to be very very long.
Overall, I gave it an "A" and enjoyed it far more than Iron Man 3 which was a huge disappointment in my eyes.