You are going to get so many opinions on this, and everyone thinks they are right. No matter what you use, stay with the name brands in the weight recommended by YAMAHA and you and your engine will feel Superior. Even the top conventional oils are just as good as the high priced full syn. oils, probably you will never know the difference.
Personally I go for price and convenience, and I have used everything in every type of vehicle and never had a problem. Change your oil in short invervals 3- 4 k miles and you will never have an oil related problem.