I know this is an older topic. I wanted to add my results from the use of a new belt. After reading this, I tried the Trizact belts. They work excellently. I am so impressed with the quality of finish and longevity.

The one thing I learned quickly though was to use the entire width of the belt. Concentrating effort in one spot on belt caused substantial wear in one spot, resulting in cupping with high spots on sides of belt. This was likely occuring on the other belts I used, however on these belts the tall abrasive structures exagerated the wear pattern. So I guess you could say, I learned somehting about my technique that needed to be improved by switching up.

I don't think this would be an issue used on a flat platen working with blade perpindicular to direction of belt travel, however I use Uncle Als integral grinder a lot. This has the blade pointed parallel to the belt. I stayed in one spot to long on the belt.

Easily corrected by moving blade across the width of the belt.

Just wanted to add my findings. Again, thanks for the recommendations above. I'm loving these belts now.