i've purchased 4 pads a while back and all their clippings have broken, but they were really good pads while they were usable
though im not really sure where u meant by 'good' riders, i'd be more than glad to test out the pads as i've got a couple bikes, both mod and stock, and a few rear wheels which i can use which includes:
26" ground echo rim
26" smooth echo rim
26" ground dx32
25" ground monty rim
20" ground dx32
20" smooth dx 32
for the front, i have
smooth echo
smooth sun rhyno lite
smooth alex dm24
teny rim with a super light grind
i thinks thats all