I have liked the 3m green corps cut off discs the best, they cost a ton but seem to last forever
My part time job buys the really cheap roloc discs and I literally went through 5 of them cleaning up some rims where you normally only use 1 for a set of rims, I was very surprised at how quickly they would just burn up. I only use 3m at my full time job and they seem to last quite a while.
I have been loving the flap discs also
