Did the infamous fair-->fair-->fair combo with DDD the other night for a sexy kill. DDD without a doubt is the character with the most moves that are super satisfying to land. His fair, f-smash, and dash attack are all so fantastically orgasmic to pull off. Other moves that deserve that spot are Charizard's up-b, Ganon's dair, Rob's dair, Lucario's super side-b for a spike kill, Lucas's new bair for a kill, amd Wolf's side-b.
In terms of balance, my friend who I am currently training in PM has decided his least favorite match-up is DDD. He is relatively new to smash, but I still found what he said interesting. He said DDD's super range, hefty power, multiple jumps with a long up-b, and the fact that he can crouch cancel straight into a d-smash for a long time has him so frustrated with the match-up. I'm sure as he gets better he'll find ways around it, but the reason why I found his words interesting is maybe DDD was designed to be abused. Like perhaps you aren't supposed to play him in a normal way. You have to abuse the hell out of his range, his jumps, his crouch-cancelling, his d-smash, his power, etc. Maybe that's how one becomes a DDD master.