The best advice here is to try both, and keep what you like more.
I've had both units a while back. Around AXE FW 4.0. It was a clear Kemper win back then. So I sold my Axe.
I've heard the new Axe firmware is great, but I don't really care to be honest.
If you are a tweaker, like spacey effects and have more fun tweaking/routing etc than playing.. go Axe.
Otherwise KPA is a much friendlier unit. It sounds like an(y) amp. It sounds perfect for me.