In reply to TobyA:
There are good and bad out there.
From my experience on mtb (sram or avid brakes depending on which bike).
I've tried most of Disco Brakes and none lasted at all, sintered were worst oddly. One wet ride and was down to the backing plate! I wouldn't buy from them again.
Uber Bike do a variety of pads, I tried their race matrix (which get good reviews on forums) I found they last forever but not the best braking unless your getting them really hot which I wasn't on the local trails.
Nukeproof semi-metallics work pretty well.
Currently using ceramic pads from Total Bleed Solutions which are working really well wet and dry and lasting so far. I will stick with these for now.