I'd be concerned about anything that is apparently abrading the rims, even making tiny gouges in them. If the pads don't contain an abrasive additive, then what's causing the wear and pulling up bits of aluminum? It could just be rubber pads plus heat, but I wonder if something else is involved. Road grit may be getting embedded in the pads and doing the damage. Maybe some pads pick up and retain more road grit than others.
BTW, @
Nerull, this isn't a rant against "fancy" equipment, as if any brand of brake pad could break someone's bank account. As always, I'm just interested in finding a solution to a mechanical problem. Whatever people want to spend on their hobbies is their own business. Sometimes cheaper is better, sometimes it's lousier. It all depends on the experience.