Nazrin for actually being fun and mostly fair.
Dishonorable mentions to
Rika for messed up SoEW hitboxes and the long stage
Rumia for Lunatic Demarcation
Letty for being boring(at least on Hard, not sure about Lunatic)
Wriggle for her midboss card(or not if I can't use this as a reason)
Minoriko due to near instant random lasers
Yamame for the opener.
Damn do I hate Stage 1 on Lunatic.(except for UFO, and the few I still play on Hard)