Those are pretty good prices. I never had the need to use micron belts for sharpening but others seem to love them.

Cheap belts are fine if you plan on using them for stock removal of untreated blades where heat will not be a issue.

You can certainly use them on heat treated stuff as well. Just make sure to keep a close eye on the heat and wear on the belts.

I find that the abrasives on the cheap belts get knocked out too easily and require frequent belt changes. Worn belts are good for are generating heat via friction with little to no cutting action. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> My personal preference is to use premium belts because they cut cooler and last longer between belt changes.