The built in toe-in profile of the brake pad keeps the contact surface in correct geometric position for powerful squeal free stopping. This profile also makes it easier to correctly install them.If you hear the screechy, squealing it's time to wipe your rims with isopropyl alcohol anyway.
I recently converted an old rigid mountain bike for commuting, and one of the upgrades I made to it was a set of these brake pads. Man, these things are popular and highly rated for a reason: they just work. Quiet, smooth braking that stops you on a dime, without sending you over the bars. They wear evenly and don't rough up your rims, so you don't get as many metal sliver deposits in the pads as you would with stock Shimano pads. Easy to install and affordable. Really, what's not to like? If you still have stock pads on your bike switch over to some Kool Stops; you won't be disappointed!
Kool stop pads don't last quite as long as those rock-hard things that come stock on all your bikes but they're fantastically effective and that makes it worthwhile to change your brake pads out a little more often.
I'm not sure if it's an error in my setup, but these brakes are so loud I have to back off sometimes, as it hurts my ears - the squealing is that loud. That said, the pads grab like mad, and I can stop safely if I need to. In that respect, they're the best pads I've owned.
I purchased the post-style pads and put them on a vintage stem-shift bike with a cantilever setup.
I bought the salmon-colored brake shoes for better stopping power in the wet. On some biking blog, I read that you should buy the salmon ones for all uses, not just in the water. Something about the iron oxide (Rust) mixed in with the rubber giving them more friction against the rim. They seem to work fine, still working on the fine-tuning for adjustment. Applied pretty hard the other day at 35 mph and got some nasty vibrations, hopefully by toeing out slightly, that will fix it. (Haven't ridden since due to crappy gorge weather.)