I think they’re good but not quite perfect. I had Hope Minis for a while, then got Avid BB7s for my gf. They were way better than my Hopes, so eventually I switched over to them as well.
The BB7s ran for a few years before the pad adjusters seized. I read recently on here that it’s worth disassembling them from new and greasing the threads inside the pad adjusters to avoid this.
The other down sides were that the cables get manky just like any other cable (even with full-length outers) and that the pad wear could be crazy in the wet. I went through a whole set of pads in one wet day at Afan. Maybe that was poor technique, but my current choice (Shimano XT hyrdros) last longer.
So they’re good, powerful, and actually more adjustable than hydraulics. Maintenance is hard to call, but I’d say they’re more maintenance than XT but less than Hope.