This is only my experience, so it's just 'for what it's worth'.
I have a 2002 Ford 7.3 diesel pickup, it weighs just a couple of pounds under 8,000 curb weight and I often pull heavy loads with it. I put slotted drilled rotors on it and non fade brake pads --it now stops in about 2/3 the distance it did before with the stock Ford set up. If there is fade I haven't noticed it, but I also have exhaust brake and all the Banks gear lock transmission stuff (well actually every thing Banks could install was installed), and I don't race it, so possibly brake fade would show up under more adverse use, I don't know. Given that it has an anti lock system the comparison between rotors is probably a fair one in that max braking is the same no matter what I do with mashing on the pedal. And like anyone that racks some miles up that has come up on occasion.
I don't know about the wear factor but tomorrow I'll be having a new set of tires installed and all the brakes and so on will be checked --that's slightly over 40,000 miles since the new rotors and pads were installed. As far as I can tell they work as well now as they did after they got set in --a few miles & stops before they really 'came into their own' so to speak.
Anyway I think they are of some benefit, at least they have been for me. BTW, I bought the truck new and ran it as delivered for the warranty period then had the Banks stuff done, and made two trips up and back to Alaska pulling very heavy trailers, before I did the slotted rotor & brake stuff --the trips up and back got easier after I did the rotors etc., so I'd say it's been a reasonable test.