Who's your favorite Frontier Brain, and why?

Extra: Who kicked you ass more often and how/why?

Pic related is my favorite, loved the whole Arcade in Platinum and her fights were fun and challenging without being a show of shrekage

I could never get past fucking Argenta though. I don't know what was up with the battle hall, but it was boring and she always ended up OHKO'ing me

I never went to the battle frontier in emerald, so no clue about the brains there