Since my engine was a brand new rebuild, i used standard 10w30 cheap stuff for break in, then after over 1k miles, i switched to Mobil1, for summer ive been running the 15w50 racing formula, but for winter i use 10w30, no leaks, no burned oil, the engine doesnt lose ONE DROP of oil. Canby for me was 1300 miles, dipstick never moved there and back. Several racers I know also wouldnt use anything but Mobil1.
But an oil question is like asking whats the best color to have as your favorite, EVERYBODY has an opinion...