I haven't used the other stuff, but my experience with POR is awesome! Need to make sure you have a good prep- meaning a bit rough- for it to bite to. ROUGH sandpaper, not just a little hit with 220. Sandblasted or lightly surface rusted metal is perfect. Once it goes on, it STAYS! Once hard, you'll have a hard time making a mark in it with even sandpaper.
Had it on the floor of a Jeep once...no carpet, and it was a trail rig, so lots of dirty/muddy feet on it, and it never wore off.
I use the direct site, por15.com or else a local automotive swap meet to save on shipping.
Jim