Not taking a swipe at anyone, so, please, no one take offense. The oil additive package fails long before the oil itself. A qt of oil is upwards of 1/3 additive package.
The hardest part of our engines, on the oil, is the forces between the gear faces in our transmissions. A synthetic is not truly man-made, as the word synthetic would suggest, but it means that engineers were able to separate out the longer, and more closely identical shaped molecule chains that slide better over one another, giving the synthetic better lubricity.
The forces between the gear faces in our transmissions, since they share the engine oil, is capable of tearing up those long chains... and can cause the oil to breakdown. The solution is to change it according to the manufacturers recommended mileage, which from the owners manual, is 4,000 miles.
I have 3 R* and run the Amsoil 10w-40 for Jap bikes with the Bosch 3323 filter. Since I don't put 4k miles on any one of my bikes in a riding season, I just change it all out every spring. For about 1/2 the cost, I could switch over to the Rotella T-6, but we still have that old Amsoil white paper on an independent lab running the oil industry standardized testing for all the many different ways oil is supposed to serve our engines, and those tests revealed significant differences in the performances of all the oils they tested, and the Amsoil came in first, followed rather closely by the Mobil 1. Others fared considerably worse, and the Rotella, not being a bike oil, wasn't included in the test at all.
Our bikes are very important to us. It's one of my main
interests and hobbies. Since the oil is the very life-blood of our engines, I just can't bring myself to cheap out on the engine oil for any reason... it's not worth a few bucks to me to place my babies at any extra risk for all that they mean, and do, for me. Heck, I could probably switch to Rotella T-4 dino, and wouldn't do them any harm... but, to save a few dollars over the span of 7 months out of the year?
Knowing I've done all that I could to take the best care of my bikes means more to me than the amount I could save.