I really didn't pay a lot of attention to who was playing whom. I knew I knew Spock's mother, but didn't realize it was Winona until the credits. Spock reminded me a bit of a young Alan Rickman. Yes, the kid playing Kirk reminded me of Matt Damon in GOOD WILL HUNTING. All the right moves, but that touch of Shakespeare Shatner gave the character (however much we sometime giggled at it) did make Kirk charismatic.

Speaking as someone who hates the actor playing Spock, i loved it.