I'm quite self-aware and know when I want things to happen, such as expectations that a synthetic oil will perform better.
But, I did, as objectively as possible perceive that the Taco ran smoother, and the engine revved more willingly on the synthetic than the regular oil.
I can in no way measure the differences, but I do know that I'm not swayed by an expectation or feeling that the Pennzoil (substitute Mobile One, if the Penz wasn't cheaper) was going to do it better.
I really do feel that the engine wound up more freely after the oil change w/o my personal notions that it would do so aside.
Again, can't verify it in any way, but it just seems to run better now.