He's a better physical match than any of the other actors cast in the movie - much better, in fact. For the others, it's going to take more suspension of disbelief.
And a LOT of it will be in the acting - comparing still photos is pointless. These are actors
, not mannequins. Quinto's job is to convince us he is Spock, regardless of his looks. In his case, his looks give him a lot of help, but he's still got to pull it off via talent.
Which is another way of saying, why don't we just wait to see the movie before jumping all over things, oh hell, who am I kidding?
And Quinto is a close enough match that I was on this very BBS, promoting him as a great candidate for a young Spock, before I even knew there was a prequel movie in the works
. Maybe I'm psychic, but my inability to pick winning lottery numbers tells me otherwise. The only other conclusion is that, yes, Quinto is a positively eerie match for Nimoy.