I enjoy watching both of them, and I'm looking forward to seeing both of them play in the NHL, whenever that is...
The problem with arguments in favour of either player is that they're all flawed, which is what makes this discussion pretty pointless...we won't know anything until the NHL season starts up and/if both are playing regularly on different teams. Having said that, scouts and gm's obviously have to make this sort of determination all the time...
From a marketing standpoint, you have to take Crosby, he's obviously more polished and charismatic to North American audiences. That doesn't help you much on the ice though so it can't be your only consideration, but it may be an edge that would steer some to Crosby's side if their talent is so close that it's tough to call. If you think you're getting a stud player either way, you take the guy who can draw fans and sell jerseys on top of all that.
Ovechkin is further along in his development because he plays in the RSL, and Crosby has nowhere else but junior to play. However, there's very little evidence of how Ovechkin will play in North America...while he was one of the few Russians to score in the World Cup, his own coach didn't trust him enough to play him consistently and Russia didn't progress far enough. So far Crosby has been better in the WJC than Ovechkin, although Crosby has played against two weak teams and Ovechkin had to face the USA first game...it appears to me just based on what I've seen so far of both (which is probably not nearly as much as most others have seen) that Crosby is more consistent, while playing against much more pressure than Ovechkin, but he's playing against worse competition. I have no idea whether Ovechkin is shadowed as heavily in the RSL, but I can't imagine that he draws the same scrutiny as Crosby on the ice. Ovechkin is just another player in Russia, isn't he? Crosby is the main target everytime he steps on the ice. That's why the WJC is good evidence in my opinion because Ovechkin will be the main guy for this Russian team.
Any further analysis beyond that would have to do with each player's hockey skills and how they will potentially fit with the team they play for in the NHL. For now, we just don't have enough information to know (well, at least I don't.)