Iíve run regular Yamaha and Honda oil in past bikes and had a mechanic recommended Specro golden when I was on my third bike, a Suzuki Hayabusa. That oil shifted better and quieted the top end noticeably. Ever since, I run at least a blend or full synthetic. I have not noticed much a difference between the full or blended synthetics in multiple brands including amsoil, specro, maxima, etc. The only oil I did not care for was Rotella because my bikes shifted clunkier. I put it in two bikes at the start of one season and found the poorer shifting occurred in a Ď76 CB750 and the hayabusa. After about a week, I drained it and replaced with a motorcycle specific synthetic oil and shifting was smooth again.
Iím not about spending stupid money on oils, unless I get a perceived benefit. The maxima line, for example, is a ester based full synthetic and costs less per oil change than most other synthetic blends with no perceived difference in performance. Itís my flavor of the month. The real test would be to send it to blackstone to compare with others for wear and longevity.
Iím in agreement with the guys that say put oil in it that meets spec and ride it because it wonít blow up BUT, I also think if you gain something like smoother shifts or quieter engine AND are willing to pay a little more, then go for it. Just my own self indulgent two cents...