With the POR you really need to scuff it with a wire wheel, or some serious elbow grease and a scotch brite pad... Its not really whats under the bed liner, it all about how it can adheere to what is being applied to... I have put Al's on a bunch of stuff, including a POR'd tub, and I am happy with it.. But like any Dyi liner, its all about PREP! I can't stess that enough.... Raptor is very similar to Al's. I just lean towards Al's because it is has a primer. Not sure if it make a dif or not, just one step I dont mind doing..... But with the Al's, vs Raptor, Al's does not come with a gun...