Since I don't have a degree in chemical engineering and don't work at a refinery, I tend to defer to those who have a vested interest in how an engine performs since they typically research this stuff ad nauseam. I'd never heard of Schaeffer's Oil until three years ago. I run Mobil 1 in my '98 Jeep TJ and have for close to 20 years (I've had it for longer) and it has never leaked oil. I've also used a lot of Amsoil products over the years, but when I bought a chip and programmer for my '02 F250 7.3L Super Duty I asked the owner of DP-Tuner if he recommended a specific oil. He told me that the only oil he recommends to his customers is Schaeffer's fully synthetic.
He has a vested interest in how his customer's engines perform when using his products for obvious reasons so I was happy to defer to his opinion. Of course, it's possible that he's a part owner of Schaeffer's or has some other motivation, but since engine performance is correlated to some degree to engine oil, and his business is all about performance, reliability and longevity I tend to think that he's recommending a product that although not cheap, increases the likelihood of happy customers who not only recommend his products, but also come back to buy more products, just as I have done.
I work in the firearms industry and these kind of debates rage all the time. When it comes to opinions on products I don't look to the guy who spent $3K on an optic and goes to the range once a month, sits on the bench the whole time and then is on a forum ridiculing others for not buying what he bought. I tend to look at someone who's choice is far more meaningful whether they're a serious hunter, LE, military, contractor, etc.
So when it comes to tractors, machinery, oil and such, I'm more likely to put stock in someone who makes a living with their equipment, for whom maintenance, maintenance costs, downtime, longevity, reliability etc., aren't simply topics for an internet forum. For the record, I don't make a living with my tractor, can deal with downtime, but I also like to take care of machines that I own the best way I can. I get satisfaction from using things hard but also maintaining them to the best of my ability which means using the best products I can afford.