Lola Pop is a decent character in Arms, though I do think the fact that she's a clown is rather dumb. I don't really like clowns in general.
I think the fighter she reminds me most of is Ribbon Girl or maybe Min Min but a bit different.
Her special power is to inflate her costume to improve defense (I guess...) and to increase her jumping/evading skills. The ability is okay, but not my favorite in the game.
I'd say she's about in the middle in the terms of the roster.