Both Mewtwo's look crap.
Charizard X looks a little better than Charizard Y.
I'm buying Y becasuse I like Yveltal. Seriously, some people need to stop thinking they completely understand why people do the things they do, like the things they like, etc. People are fucking different. Different Pokemon appeal to them. Deal with it.
Seriously. Some people speak on things like theirs is the be all end all opinion. Welcome to the internet I guess...
On a side note, I'm kinda glad there's only 70 new ones to memorize. I'm already hard pressed on remembering all the Gen 5 pkmn and their typings and base stats and such and I played the hell out of those games.