I don't have a UOA - so take my subjective evaluation as you will!
My 97 Miata didn't seem too happy with GC. The little 1.8 got pretty noisy and lethargic up towards the top of the RPM range and it burned 1.5 quarts or so during the roughly 4000 mile interval. It also felt a bit down on power. Normally, this engine burns very nearly no oil - with Mobil 1 10W-30, Castrol GTX 10W-30, or Mobil 1 0W-40 (and burns only a little with Mobil 1 5W-30). The 0W-40 is my current fill and feels pretty good so far, although it's only been 500 miles.
On the other hand, my wife's 2000 Mountaineer with the aged 5.0 seemed to perform very well with GC. However, we tried Mobil 1 5W-30 in the truck and get better gas mileage.