Good? Kat and Eve are basically free wins. I wouldn't call them particularly fun to play, though.
Ryze gets the runner up award in both categories if you find hitting buttons rapidly to be fun and don't mind needing 20-30 minutes to hit full power. --- 'This guy has really mastered adventuring. City burning down, populace about to be sacrificed to god knows what...better loot everything'
syndra can be loads of fun but she has some really weird mechanics and one of her skill shots is actually a skill shot on another skillshot to make the third skillshot so yaaa you miss alot --- ---violence, if it isn't allready solving all your problems, then you're not using enough of it---