This is a tough one because I like them both. D= Haxorus is more of a Dragon Dance physical attacker, while Hydreigon is more special based; and both are pretty powerful! Art wise, they both look amazing too; Haxorus looks like a dinosaur based - dragon with dusks and Hydreigon looks like a dark evil dragon...I use Haxorus a lot more, so, I GUESS I'd prefer him, but, I dunno, both are still amazing~