Sky, I haven't bought a lot of sandpaper from them but what I have works well. The main stuff I have bought from them is belts for my stationary belt sander. I used to go through a bunch a belts, since I got there belts I haven't had to buy any more.
Well I did by quite a few.
I have two sanders right now the Dewalt and PC. They have served me well over the years. The only reason I have two is that the Dewalt had a problem several years ago and I had to take it to one of their service centers for repair. While I was waiting I got the PC to use on the project I had going right then. I will admit that haveing two with different grits on them is handy.
However a couple of years ago I was really looking at the Festools. I really wanted better dust extraction from the sander. The Festool sure filled the bill.
But funds were not available at the time so I didn't get one, shucks! Maybe some day.