I originally changed from the stock shimano pads on my LeMond to kool stops. But I did not like the feel of the Kool Stop pads, I thought they felt spongy. A couple months ago I switched to Swisstop pads (green). I like the Swisstop pads much better. To me the feel and stopping power are better than the kool stops and the shimano pads.
I have never experienced any squealing from the Swisstops, but I have only had them for a couple months, but, when they wear out or start to squeal I will replace them with another set of swisstops.