Honestly, I will play most of the heavy characters, such as Bowser and Donkey Kong. I'm actually looking forward to playing as King 'Triple' Dee. He has an interesting moveset, such as his down-Special Jet Hammer and his Waddle Dee Toss. The Waddle Dee Toss might not be as affective, due to most people knowing how to catch items that are flying toward them.
His Final Smash is something I would have expected from his character, leaving the work to somebody else. And his moves remind me of that one Kirby game in which you fight him in the boxing arena. I have forgotten now what the video was called, but it was shown on Smashboards somewhere. Even the flying attack is similar.
All in all, quite the unique character that they have. I look forward to playing as 'Triple' Dee. Though I doubt that I would main him. If I took the time to practice with him, I might possibly main him, unless Ridley is playable. I would use Ridley over most characters other than Bowser for that matter.