Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
The only thing i don't like about Hydreigon is that he was released in the 5th gen along with with a lot of fighting types who are usually bulky enough to absorb an attack and completely face pwn him. But i still give him my luvdiscs :P.