Here's the thing, I'm not actually gonna dissuade you from subbing DHD, but just be wary if you do so. Don't get me wrong, he's worth playing and worth putting time in to, put you really need patience and you need to put in a lot of time. You gotta learn the set-ups, you gotta learn your KO tools, you gotta learn your combos, you gotta learn what's safe and what's unsafe, and you gotta learn your MUs, you can't throw yourself into DHD and expect down-throw in to a million aerials.
He's really fun to play as though, you feel like you're trapping your opponent with all the projectiles, and when things go your way, it feels good.