@JC Daniel , They tried to sell me on hook and loop many years ago, but my opinion was that paying as much as twice as much per sheet did not add up, even though the hook and loop can be reused. It not a cut and dried issue, for shops doing lots of small jobs, hook and loop can make sense, but if you find yourself wearing out discs before needing to use another one or switching to another grit the majority of the time, sticky is probably fine. Also, sticky discs can be reused if handled carefully.