First off I am a fan of both products.
I used Eastwood's Epoxy Primer then their Extreme Chassis Black. I am very happy with the epoxy as it is tough as nails. The Extreme Chassis Black is good, but does scratch and can chip just like any other paint. But the good thing is you can just sand it a little and spray more on with a rattle can.
I knew of POR15 at the time I was doing my frame but chose not to use it because I wanted to spray my frame, not brush it. Spraying POR15 requires a fresh air respirator and I do not have one. I have since used POR15 on the inside of my fenders and under my cab and I can say that stuff is extremely tough!
The Pros, that stuff is tough, I have had to sand it off to do some welding and it is hard to remove even with a wire wheel! Hit it with a hammer, nothing happens.
The Cons, it is harder to deal with since you have a certain "window" of time for topcoating. If you miss this window, you have to use their etch primer. The toxicity is a negative as well, and it needs to be topcoated with a UV resistant paint (maybe not for a frame) but I would do it anyway. And finally, it is expensive!!
If I had to do it over again, I would still go with the Epoxy Primer and Chassis Black. Just simpler, less toxic, and easy to fix scratches.
