I have personally used the Omni epoxy primer after switching from regular PPG DP40 (at that time). While the Omni epoxy is suppose to be close to regular DP, it is not. We used it in the shop for about one and a half years, and actually at that time, had a few cars come back for peel due to the epoxy primer. I threw the rest in the garbage and went back to regular PPG DP. Never had another issue. After finding out about SPI's epoxy, I am going to call them and get me some of that stuff. I am sold on PPG DP, and we have done several tests using it over the past twenty years or so. One test was we sprayed some black iron, threw it outside the shop and left it. We would pick it up from time to time and check it out. Five years later that DP was still on the part protecting it from rust (corrosion). This was through harse winters too. DP reminds me of the product (Zinc Chromate Primer)we used when I was with the USAF as a Airframe repairman. Even smells the same. I would never use Omni epoxy again. I will be trying SPI's epoxy though.