It's not alarming that many people use this oil, and many people tend to gravitate to the companies that happen to have the best marketing as well as the easiest accessible products. Hell, you can walk into any walmart and buy yourself some. You can walk into any super market and get yourself some as well. I've been at it, and in the engine building business for quite some time, so I get first hand experience to look into these engines season after season and year after year. We study failures very closely. Years ago I was a huge fan of Mobil synthetics and that was through the 80's, and as the times changed, so did the Mobil product, and in my opinion, not for the better. I've witnessed just an excessive amount of tapet failures on Mobile oil and I have gone away from that mass marketed and mass produced product. My personal choice for an easy to get oil, is Valvoline VR1 Racing non synthetic. the VV 205 is a 10-30 and the VV211 is the 20-50. We use this in our engine shop and it does have 1100 ppm (Parts per million) of phosphorous and 1100 parts per million of zinc. It's the phos content that really protects that metal to metal interaction in the engine. The mobile along with many other "shelf oils" have less than the limit of 700. 700 is the legal limitation for zinc and phos content to be sold on a shelf. Some other oils that are really good in my opinion are Synergyn, Shaffer, Joe Gibbs and Amsoil. Some of the oils I mentioned have close to, if not over 2000 PPM of zinc and phos.
I have Valvoline VR1 Racing 20-50 in my 117 S&S engine.