I had my first ever rim split (really impressed by the magnificent sound - like a small explosion!) coming down a hill into Castleton in the Peak district. Rims not new, but not overly worn before the trip- but eight days in bad weather carrying camping gear and diverting myself, through a combination of map reading mistakes and a wish to enjoy wilder country, down some very stony tracks, I am certain meant the brake pads, (Shimano inserts) picked up tons of grot which led to the rear rim's premature demise. I had been moaning about these new pads for ages (my friends will be yawning here and nodding bored agreement) and was sure they were wearing out much faster than the old fashioned ones I had on my (very old} centrepulls. Now I am sure I was right- have changed to the Koolstops and will see how these go. Already they seem to be wearing better. I looked at the Swisstops, but didn't buy. Yes, they are expensive, but to be honest, if I hadn't been slowing down on that descent due to rain and ascending car, I may have been going at around 35mph- I do not wish to imagine what may have happened. So if I find they are better than the Kool Stops I will get them, if it saves money in the long run.