Well, considering the size of ExxonMobil and their overall advertising budget, I would think that Mobil 1 specific advertising would be such a small drop in the bucket that it might add a penny a qt, or maybe a penny a gallon, to the wholesale cost.
Mobil 1 has proven to be an excellent product over the past almost 30 years. Haven't seen anything that would substantiate that it is not still an excellent product.
Base stocks are pricey, additive packages are pricey. Whatever suits you--some folks will drink "Dixie Belle" gin, while others insist on Beefeater, Tanqueray, or Bombay Sapphire. Personally, if I couldn't, or wouldn't, use or get AMSOIL, I'd go with Mobil 1. I won't use a non-synthetic if it was given to me.