The PAPS is the way to go. Do it right and it will last forever. My current garage I put 100% solids epoxy on with urethane topcoat, and it still looks really nice. Although my next shop will have the PAPS topcoat.
It's a water vapor transmission issue. Applying penetrating vapor block to the floor is about the best thing you can do. Although there are other ways to go about, I just mentioned the cheaper of them.
