Yes, the science was in smithereens (Red Matter? O RLY?) - and yes, there are certain aspects of the plot you could shoot a photon torpedo through - but dammit, the reason I loved the original series was the characters... and they NAILED the characters.
One of things I confess I was a little worried about while reading preliminary reactions to the movie was that the cast appeared to have been judged not so much on how they played their characters - but on how well they played the original cast playing those characters. Which was a little unfair to both casts. But instead of that, what I largely got was a picture of how the characters which I originally knew and loved actually came to be - and I LOVED that. Of the lot, I really do have to single out Bones McCoy. He was absolutely tone-perfect. Would have been worth the price of admission all by himself.
I am SO going to see it again (I am told there's a secret Tribble in the movie somewhere, I have to go find it!!!) and this is one of those movies that is going on the to-get list when it gets released on DVD in the fullness of time.
(And you're talking to a confirmed Trekkie of years standing. When they ended the movie with Nimoy intoning the iconic "These are the voyages of the starship 'Enterprise'... " intro, I said it with him. Word for word. Please, when carl_allery and I roomed together at the Japan Worldcon, we needed a four-character code for the hotel safe in the room, one we could both remember. We used the registration number of the USS Enterprise...)