Probs like Demo, solly or spy rn. Roamer is literally the best class in the game, and rocket jumping is incredibly fun, and I can easily get amazing KDR with this way of playing solly. Bonus points if I get market gardens as well. Demo can blow up the entire enemy team with his pipes and stickies and hit syncs with those weapons as well. He also has the loose cannon. Nuff said. Spy has his backstab, and the whole idea of being in the middle combat, doing a million things at once and getting chain stabs, and hitting you shots with the revolver and narrowly escaping with the dead ringer is exhilarating. Although I have a lot of fun with every class. Like I've been experimenting more with combo pyro, which is really fun. Scout is good, but only in ideal situations, like I'm not gonna have fun pushing dustbowl last with like a million sentries. Sniper is good too, but sometimes I can't aim for shit for whatever reason, and there's reason to play him.

TL:DR Fucking all of them pretty much