After 4 coats on mdf with a smooth foam roller. Roller grade duratex. Added a tad bit of water to the last coat. It covers well, but YES it is hard to make sure no roller marks. If you basically lay the roller on the surface and backroll with the roller just sitting on the surface. This is a test piece of mdf to see what type of finish Im going with. The texture is very very minimal by using a smooth foam roller. Next I will use the roller, sand with 400 grit to knock down the high spots, and roll again.