Yes, I was surprised to find that Mobil One is not true synthetic, but I'm surprised that you would turn your back on it for that reason. Mobil One has been around for about 25 years or so now and is a proven, tried and true product. It's results that count and Mobil One delivers results.
I personally will not go away from Mobil One for such a reason. If the day comes when it is not providing good results, I will reevaluate at that time. I really don't care if it's made out of horse manure as long as it works, and Mobil One works.