I've used the Sherwin Williams Dimension 2K single stage enamals. These are comparible to PPG's Omni but, I find they cover better than Omni. Totally satisfied with the results. There is a base coat/clear coat system in the Dimension line as well. The 2K single stage paints have a super high gloss. There is a matt additive available if you want to flatten them. Are you painting a high gloss finish or camo?

I believe the high end Sherwin Williams line is Ultra 7000. Haven't used it though.