Rotella 15-40...good stuff and very inexpensive.
Suzuki, Honda, Yamaha oil...just an fyi, these are not oil companies, they do not produce oil. They make a deal with an oil company to produce, bottle, and distribute oil for them. Oh, surely they have some special blend just for them you ask...ugh, wrong again. To have a refinery create your very own special blend would cost millions of dollars and simply does not happen.
I work for a large oil corporation and we have an agreement with a major automobile manufacturer to produce, bottle, and distribute oil for them under their name. It is the exact same oil we sell under our name but in their bottle and 4* the price. Yet, folks insist on it and purchase it at their dealerships because it is "made" by the manufacturer and they know what is best...NOT!
Now, I can not tell you exactly how companies like redline, royal purple, maxima, etc work...but I have asked about it and the general consensus is there are varies grades of base stock oil. Obviously higher grades are better and more expensive. These companies either purchase whatever grade of base stock and sell it as their own, or place their own additives in at their facility...my money is on they are just reselling under their name and doing nothing to the oil but the marketing!!!
Each has their own opinion as I do and the above information is just food for thought. If you think brand X is the greatest oil ever made then run it and be happy. I am happy with my $7 per gallon Rotella!