I have. I think that a fixed caliper with multiple pistons is the better arrangement overall. This is always true, but becomes more important the harder that you drive the car. If you don't drive it hard and simply want something better than drums then the sliding caliper system is an easy choice. If you are racing the car, or tend to flog it hard at times then the fixed caliper is the better choice. If the K-H calipers have some Achilles Heel (other than rarity and the occasional stuck piston) that worries you then perhaps they're not what you should buy. I don't worry too much about cross-breeding in my project vehicles. For instance I have considered using the 4 piston, fixed calipers off of a late model Toyota Tundra on my '70 Ford Bronco. That isn't for everyone, and it sounds like it's not for you either.