My preference when checking out TMCs:
SS Tier
Falcon (so many possibilities keeps these from getting stale)
S Tier
Link (difficult char to master, but lots of options)
A Tier
Samus (only because I'm amazed people (Ricky) can actually somewhat combo with her)
DK (but only if it's something beyond Uair xn)
B Tier
Fox (the more shines, the better!)
Jigglypuff (teleports and pounds are nice)
Ness (DJCs are best)
C Tier
Luigi (always satisfying with the finishes)
D Tier
Yoshi (some cool recent stuff with Dairs (Ricky), but most combos seem stale and boring to me)
Mario (slow, boring, unsatisfying finishers
Kirby (i die a little inside every time i see a Utilt)
Pikachu (my least favorite character to watch in-game and in TM)
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Falcon has been and always will remain my favorite. In the right hands, there is so much variety and has the potential to be something never done before with each and every combo.