I don't waste time with any abrasives except 3M. Other than that, I'd say to try and avoid the "Lowe's exclusive" sheets with the gummy back. They probably work good for people who are not very sophisticated sanders, but the stuff tends to stick to my sanding blocks, and it stuck to the pad on my 1/4 sheet sander and tore up the foam when I pulled it off, so I had to buy a new backing pad. I think you can get non-coated without that backing, but non-coated is great for softwoods, not so great on much else.

m