I can comfortably start playing on Adept, but from there I might have to eventually switch it back down to Apprentice, or even Novice depending on the enemies I face.
Anything above Adept though... it baffles me how some of you manage to play on such levels. When I've played on them I get killed within a few hits, and it takes so long to kill them, I just don't get how you guys do it.