I used POR 15 on a pontoon trailer i built. It has a matched top coat on it to protect it from UV. the steps and other vulnerable areas do not have any wear spots, chips, scratches, etc. after 4 years of hard service.
I plan on using POR 15 on the chassis of my 41 pickup very soon. I am not familiar with the other products mentioned, but I am very please with this stuff. I tried hammering it off of a piece of scrap metal and couldn't.
