One mistake that was made a few times in the very early days of the ST1100 that gave EBC a bad rep was in addition to the FA142HH, they made another set of pads in GG friction rating that also fit the ST1100. People who bought them didn't like their stopping ability (because they are one level lower friction rating than the OEM pads) and cursed EBC for making lousy pads. I've been using the EBC FA142HH for over 20 years, along with Galfer once, and have been happy with all of them. I also owned the bike since new, so OEMs were my first set for reference purposes. I came from a sportbike to the ST1100, so I was a pretty aggressive rider in the early days, and didn't notice any difference between the stopping power of the OEMs and the EBC HH rated pads.
As far as rotor wear is concerned:
1. I don't know much about how the various friction ratings are determined, measured, or calibrated, but there is a standard that they all work to. It would seem that any HH friction rated brake pad is going to be more or less equivalent to any other HH rated pad in regards to how well it stops, and how much it wears the rotors.
2. just like with tires, the rotor wear rate is highly dependent on how the bike is ridden. If you cruise the Interstate at 75mph for hundreds of miles at a time, your tires are going to last longer, and your brakes aren't going to be used much at all, so you'll get a lot of miles before your rotors wear out, just like with the tires. If you ride twisties aggressively and are constantly on/off the brakes, your tires and your rotors are going to wear out in less miles than if you mainly ride freeway. So, one rider may get 150k out of a set of rotors, and another rider 50k, using the same pads, it all depends on how they ride. Just like one rider gets 15k out of a front tire, and another rider gets 8k.