Only going off the ones I've personally seen.

Calibur: Cool suit, lots of dark visions. Though if I'm honest, I think the visions wouldn't bother me too much, since I live in a world where you can see every bad end imaginable, and with my boundless optimism and living in the present, I wouldn't be a bad calibur.

Demons: I already feel like an old man (along with other fun things going on in my body), if I really let loose my inner wickedness, I could be an Olteca Demons. Though, I'd probably be more of a George, and maybe a Hiromi if the situation demands it.

It's a toss up between those two for me.

Honestly I'd pick TheBee. Yeah, TheBee's track record across all it's users has been filled with severely large "L"s, but I'd still be down to personally experience using Clock Up.

Odin. That Time Vent.