I know this isn't a Canti Vs Disc comparison, but I'd like the chime in with my experience of canti's so far.
I used Shimano XT/SLR canti's on my 1991 1000 LT from Calgary to Vancouver this summer through the Rockies. I used Koolstop Salmon pads front and rear. Total weight including myself and the bike was around 210-220 lb.
These brakes saved my life more than once, even in wet conditions, or while descending 8-11% gradient roads down and through the mountains. The front brakes wore about 30% so far and the rear 15%.
My bike stops better than my friend's new Kona Dew disc brake commuter. I know it's a weird comparison, but I realized I don't need disc brakes when having a good cantilever brakes and pads makes a huge improvement.
With respect to rim wear, some rims wear more than others, but that is to be expected. I like to think that the wear of a rim from braking should last the lifespan of the use of it as well (rim integrity from riding around). If my rims get to a point where the surface is worn from braking, it's probably time to replace the rim as well as the structural integrity could be compromised from years or miles of use.
