Well mentioned it sometime before but I guess this would be a full break down of my experience.
P4AU: Minazuki, because he is really easy to learn and supposed to be strong. Did ok but didn't actually like playing him that much because I can't open someone up when they are blocking, or my command grabs are too obvious.
Tried Kanji for a bit, but that probably doesn't count.
GG Xrd: Started with Sol, and then stopped playing the game for like a few months. Sol looks cool and his combos look great, but I actually don't like playing him for the same reasons as Minazuki in P4A.
BBCP: Nu-13 seems like a very simple character to understand at a low level. But I played like, maybe 60 or so matches max and lost most of them.
Xrd again, but we already talked about Ky. I like it more than Sol, mainly because simple, easy to understand.
Bonus Points:
EXVS
Blue Frame. It's bland, average, nobody plays it.
ZZ. Because damage! And super armor.
Norn. Because its OP, it's easy, you don't stop pressing buttons. Also it has a ton of gimmicks that you don't ever need to use to beat anyone.