I gave it four stars - I don't know if it's the best Trek of all time, as only time and repeated viewings will decide that for me. It definitely felt better than a 3.5 vote, so there you go.
I thought they did as good a job of balancing multiple masters as could be expected. They needed - no, wanted - to pay homage to the past. They needed to bring in new viewers to make money. They had to tell a good story, one that would hold the attention of thoughtful science fiction fans as well as people whose idea of "skiffy" (as Harlan Ellison would say) is formed completely by Star Wars and Independence Day.* I think Orci and Kurtzman did a better job servicing all these needs than anyone could have expected, and their Trek-loving script was given an A+ treatment by a non-Trek-loving director in Abrams. Perfect combination of interests and skills.
I loved Bruce Greenwood's portrayal of Pike. I was genuinedly inspired. "I dare you to do better..." And him pulling the weapon out and shooting the Romulans when Kirk was saving him was awesome, showing that he was broken but not defeated. And "I am relieved." I would love to see this character again in the sequels, serving a role for Kirk similar to how Pellew serves as a mentor for Hornblower. (After all, as Spock Prime says, Kirk Prime looked up to his father and was inspired by him to join Starfleet... Pike in this timeline is already serving that role.)
Nimoy was right on as an aged Spock. I don't know how much of his quietness and his touch of frailty was acting and how much was Nimoy's actual condition (I suspect people are not giving him as much credit for acting as they should) but I thought it was right on for the character. And I love that they did not kill him off in the end, like 95 out of a 100 dramas would have done. It's ironic that Spock Prime is now older and likely retains more knowledge of Vulcan culture than his father, and important consideration in a Vulcan-less timeline.
I've never seen any of Simon Pegg's movies, but I'm going to seek them out. He was genuinely funny, and kicked the movie to another level when his Scotty arrived. (One of the few things I disliked about the movie was his alien sidekick, who seemed to step right out of Star Wars and onto this movie. But there wasn't much of that character, so no big deal.)
It's a shame that the main female character was basically written as the female love interest cog in the plotwork, but luckily Zoe Saldana did a lot with Uhura. She's obviously got a lot more going on above the shoulders than the equivalent character would have in a lot of other movies. I found her Uhura to be a lot more integral to the ship than Nichelle Nichols' was (which was no fault of the actress, but rather the scriptwriters and their times, methinks).
That brings up a point that I wanted to make about this movie. You get a real sense that every single person on that bridge was extraordinarily intelligent and gifted, and had worked hard to earn a place on that bridge. So refreshing from most entertainment these days, filled with slackers and people made heroes for thumbing nose at authority. It was great to see a work where some things need to be earned. (Yes, Kirk thumbs his nose, but he demonstrates competence while doing it, so that it is effective and is rewarded rather than punished.)
Karl Urban's McCoy has already been praised. I'll just concur, and say I'm relieved that a line that sounded kind of twee in the previews ("Space is disease and danger wrapped in darkness and silence") was far more awesome in context.
And I MUST have that image of Enterprise in front of Saturn as my desktop background soon. Please, please, Paramount? I heart starship pr0n.
All in all, I only see one movie a year, if that. This was so good that I hope to go again to see it in the theatre, something I've never done.
*No offense to lovers of those two works. SW is science fantasy/pulp, and ID4 was a summer blockbuster with SF trappings.