I've always been a fan of Texaco Havoline, available down here in New Zealand as Caltex (a joint company between Chevron and Texaco.
I know some time ago that the Texaco CART cars used nothing but the dino Havoline Formula. It had an extremely robust additive package. So the same additive package in a synthetic basestock must be an excellent PCMO.
In my Honda I now use Caltex Havoline Energy SAE 5W-30, its a Texaco Europe based product which is made with Group III base oil, I've seen tests which showed it gave up to 6% fuel saving and excellent UOA results.
Here in New Zealand, Caltex don't advertise Havoline Energy as a synthetic despite it being Group III - that differentiates it from their Havoline Synthetic which uses PAO.