22 is uncomfortably bright for me, unless I'm in a bright room or outdoors, in which case the light doesn't much come into play.
I keep it around 15. For me, I want a more print like experience, not a more LCD like experience. I know it's front lit (well, more parallel lit, really), not back lit, but when it's that bright, it feels like an LCD.
Edit: just tried max light again as you suggested. Now I remember the other reason I don't do that: the blobs are even more noticeable. I have a stark white screen with teal and plum blobs in the middle. It's kinda artistic, actually