Best "on paper" might be specialty oils like amsoil, mobil,maxima, spectro, or even the diesel oil. Best "in the bike" for wear and longevity of the engine the paper #'s aren't so clearly evident.
For every glowing testimonial about brand A or B boutique oil. There are 100's of bikes out there doing fine and lasting a long time on brand nothing special off the shelf car oil. The things that seem to shortenen the engines life that I have seen, like filters, valves not adjusted, improper fueling, poor parts machining and tolerance, couldn't have been helped by super oil. A couple low mile motors recently have worn cams lobes run on red wht blu oil, not the oils fault, rough machining on the buckets got them. Another in the shop, 98k ex500 twin, looked great everywhere inside and still pumped spec compression. Owner bragged he religiously changed oil every 5000 miles with brand C (car) oil 10w40. LOL, by bitog forum data it should be goin to the scrap yard, heck it probably speant 1/2 it's life with 20w in it? And I know it speant many years on the track too?