I am only a "casual Trekkie" - not a new-style Trekker - in that I've seen several of the original Star Trek shows, and at least know who Capt. James T. Kirk, Spock, Bones McCoy, Scotty, Sulu, Checkov, and the others are.
That said, I thought the movie was excellent. They really did a nice job in filling in the pre-story, and fit the characters nicely. And yes, both leads, Zachary Quinto and Chris Pine, hit it right on their characters. They may not look exactly like William Shatner and Leonard Nimoy, but they embodied the spirit of their characters perfectly.