IT WAS BRILLIANT!!!!!
I am a serious Star trek fangirl from way back. I've seen every episode of TOS and TNG. I can name any TOS episode in less than 10 seconds (It was a drinking game in college - I kid you not)
So when I tell you that this movie was awesome and everything a true fan could hope for, you know where I'm coming from.
I will try not to be too spoilery - I went in knowing less than nothing about the plot - I wanted to see it without bias - so I won't be giving too much away.
Each and every member of the crew was perfectly cast.
Karl Urban as McCoy, whom I had doubts about, was hilairous and I wanted to see more of him. I never was a big Bones fan but Karl made me love him (Doesn't hurt that I'm a huge Karl Urban fan EOMER!). When he finally spouted "I'm a doctor not physicist" line" I squeed with joy.
Simon Pegg doesn't show up until 1 hour in but when he does I was giddy and he was a little more comical but with good reason he gets drafted to the Enterprise under unusual circumstances.
Checkov is wunderkind we've always been told he was but never had a chance to really show in TOS. And Sulu fences. Uhura is the best fleshed out of the "minor" crew members and she's a tough confident woman who knows her own mind.
As for Kirk and Spock - the dynamic was perfect. Chris and Zachary play off each other with a rhythm reminiscent of the originals.
As for the plot - it was a wild ride. I thought it was tight and made, as Spock would say, logical sense.
My recommendation is if you are undecided between ST or Wolverine - don't think twice. Star Trek is everything Wolverine was not. True to canon and yet original and fun and exciting and well paced. Also, my kids who have seen a only a handful of TOS episodes thought it was great. We all want to see it again!
I am happy to elaborate on any of these points, so be aware that there may be more specific spoilers in the comments.