I use the 30-90 set and have on my Yamaha since 1988 or '89. I like them better than others. That's why I use them. I used to own a couple of stores and had gotten them for some local guys. Back then ALL bass strings were expensive so didn't get changed as much as they probably should have. I can buy retail now for less than what my dealer cost was back then. since I had so many around, keeping these guys supplied, I tried them. I haven't used anything else since. I used mostly rotosounds since I was about 16, always roundwounds. The half-round and brite-flats were really popular but I never had any trouble with frets or fingers using roundwounds.
After not playing much for the last 15 years I contacted KS to see if they were still in business. I ofund a website and started emailing. About the 3rd email I realized it was Ken that was answering me. He's as nice and helpful as he was back 20 years ago.
This is a lot more than you asked, huh? I guess I should just say I like them. For me they are just perfect. They thump, pop and slap just like i want them to. I still can't find them in stores very often but the internet helps out now.