have a pair of the smarty pedals (use eggbeaters and candies on my other rides)... the smarty set now has about 2,500 miles on 'em and still no problems... but as others have pointed out, they are NOT rebuildable, so when they go, they're gone... i got 'em at a good price, so i popped for them at the time...
i notice no difference between the smarty and candy pedals... OTOH, eggbeaters gave me hotspots on my previous shoes (661s)... i now use stiffer-soled shoes, so this hasn't been a problem...
p.s. i'm beefy, but i'm not a masher, so YMMV...