While it should be taken with a grain of salt, the Lubrizol relative-performance comparison tool provides some insight.
Lubrizol relative-performance comparison tool -- PCMO
I overlooked to include the Noack values for the newer MB specs: MB 229.5, 229.51, 229.52, 229.6, and 229.61 have 10% Noack. MB 226.51 and 229.71 have 11% Noack. MB 226.5 and 229.31 have 12% Noack. MB 229.3 has 13% Noack.
You can use the Lubrizol relative-performance comparison tool to see that the oxidation performance as well as deposits performance are clearly correlated with the Noack across the MB specs, as well as when you compare the MB specs to the BMW specs with 13% Noack. This is because the Noack is correlated with the base-oil quality, and oxidation and deposits are correlated with the base-oil quality.
MB 229.71 -- the only 0W-20 and 5W-20 MB grade -- has 11% Noack but the best performance of all MB specs, better than the MB specs with 10% Noack. This is because it's effectively 9% Noack when compared to other specs in terms of the base-oil quality, as the Noack increases for a given base-oil quality when the base oil gets thinner. I had already explained that you need to compare the Noack values for the same base-oil viscosity (in terms of the CCS performance); otherwise, you need to account for the thinner or thicker base oil, which results in higher or lower Noack, respectively, for the same base-oil quality.
Moral of the story: The Noack volatility for a given SAE xW cold range/base-oil viscosity is the primary performance indicator, as it defines
how synthetic an oil is. The main difference between the Euro oils and the ILSAC oils is the minimum requirements for the base-oil quality. Some brand-name ILSAC oils sold in the US have excellent base-oil quality and they are not inferior to oils with Euro specs, if not superior. As an example I wouldn't hesitate to use the fully PAO-and-AN-based Mobil 1 EP 0W-20 or Mobil 1 AP 0W-20, in fact even the half-PAO-based M1 AFE 0W-20, in an engine that specs MB 229.71 or some other Euro 0W-20 OEM spec, which typically utilize inferior Group III+ base oils, as long as there is no warranty concern. Likewise a high-quality GM dexos1 oil is not inferior to a Euro oil in the HTHS ~ 3.0 cP range, and a high-quality GM dexos2 oil is not inferior to top Euro standards such as Porsche C30 or VW 504.00 -- in fact these oils usually have all these specs simultaneously.