This is simply a great movie. For those of us who grew up first on the television series, then the series of motion pictures, then "The Next Generation," this is the TV series on special-effects steriods, and in my opinion the second best movie of all Star Trek movies, next to "The Wrath of Khan."
The first 20 minutes is jarring, and you have to pay attention. It runs the viewer from Capt. Christopher Pike (played by a one of my favorites, Bruce Greenwood), to the evil Romulan Nero (Eric Bana, sans Hulk get-up), to the young Spock, to the risk-taking James T. Kirk (played supremely in this role by Chris Pine), then finally to the late-teen Spock who chooses Star Fleet, played by Zachary Quinto. Yet somehow the editors managed to keep the essential plot lines straight. Kirk is exceptionally bright, but a hell-raiser. Uhura (Zoe Saldana) is as beautiful as can be, and ironically has no interest in Kirk but rather is in love with Spock. Kirk proceeds to get beat to a pulp by almost everyone in this movie. (First it's cadets from Star Fleet, then Spock, then the Romulans. You begin to think Kirk was taught to fight at UN peacekeeper school).
Above all, what makes the movie is the development, on multiple levels, of the friendship between Kirk, Spock, and to a lesser degree, Bones (Karl Urban) and Scotty (Simon Pegg). John Cho plays a straight Sulu, thank God, and Anton Yelchin does a good job as Checkov.
The plot revolves around the "prime"/older Spock (Leonard Nimoy) trying to save Romulus in the future, and failing. Somehow, the evil Romulan Nero comes through a time warp to the past to destroy Vulcan out of revenge---and to make the young Spock watch!
Don't get wrapped up in debating the "time continuum" stuff, just go with it. There is a glitch with this at the end (the same person cannot exist in two places at once, or two people from different times can't co-exist, or . . . ah, forget it).
Instead, just enjoy the origins of the comeraderie, the sexual tension between Spock and Kirk over Uhuru, the one-liners, and above all, the fantastic way the actors adapted the characters to their own personas while maintaining much of the original Kirck/Scott/Bones/Spock personalities. At times, you can almost see Shatner coming through Pine; unfortunately, at times, Urban tries a little too hard to "be" Bones, and of all the characters, his is the least developed in terms of motivations or past. But the friendship between Spock---at any age---and Kirk is wonderful, if rocky at first. When Spock prime says to Kirk, "I am, and always have been, your friend," it brought a tear to my eye as I recalled Spock dying to save the Enterprise in "Wrath of Khan."If CGI had existed in 1966, instead of cardboard sets, this is what that Star Trek might have looked like. Enjoy. Live long and prosper, unless, of course, you are Spock prime speaking to Spock in which case, as he noted, "It would be self-serving."