Some flaws but mostly a good watch. Just went to see the movie a second time. When I watched the first time I was pretty overwhelmed by the amount of action, but not surprised, because this is in the end a sci-fi action movie. I liked the storytelling and the plot, and it works very well in 3D.
But the second time, I noticed some continuity flaws that is not necessary with a huge budget like this movie has. For instance, when they all get in their pods to quickly evacuate the Enterprise there's no time to change clothes, right? And the pods are very small so inside it would be a hassle an probably take more time than the actual trip is. Still Chekow and Kirk, being the last ones to leave the starship, manage to land their pods and get out in a complete different attire. Not just an extra jacket, that could have been inside the pod, but pants, shirt, everything.
And I noticed the second time that Karl Urban was actually pretty off in this movie. He tries to add some sort of Shakespearian gravity to Bones and that mainly in the way he speaks. That results in a flat and unbelievable character. Haven't seen that before from him, but I felt in this one it was distracting and therefor failed the 'holy trinity' of Kirk, Spock & Bones. But luckily his part in this movie (and if I remember correctly, the others too) is mainly in service of the other characters and he doesn't have his own storyline. So the distraction was minimal.
And I was a little disappointed that Kirk, after losing his ship and some of his crewmembers, did not ever show any regret, sadness, anger or pain for that. As well as the other main characters, like Zulu, who talks to Krall as if they are from competitive teams at a sportsevent.
For the rest, I really enjoyed the movie again, the pace is good, actionscenes are numerous and the actors are mostly true to their character. Not as good as number 2, but certainly a good competition with most blockbusters we see these days.