I use the KC clutch. It was in my 88 when I bought it and was said to be about 6 months old. I like it. The pedal effort isn't too bad, but it's definately not like a stock one. My wife has driven it and never complained about it, but when I was driving my friend's Nissan for a couple of days, I kept slamming my left foot into his floorboard because I wasn't used to his extremely easy clutch

. I've never had any slipping problems with it, it grips well for me. However I don't run slicks yet, so it's not like I really abuse it too much. I've always heard good things about it from others who use it and I'd buy it again.
Dave