One of the best car forums I ever took part in had a rule that many sites would do well to copy. NO POSTS ABOUT WHICH MOTOR OIL IS BEST. The moderators would delete them immediately. 

Already on this thread there have been dubious statements of "truth" for which there is no verifiable proof and no way to provide such.

The way I learned it as a teenager about 45 years ago is that if the oil is green and the can says "SAE" on the top it's good enough. The main thing, by far, is that you've GOT oil. That was from a former Air Force jet mechanic turned factory trained Porsche/VW mechanic, to this day one of the top three or so mechanics I have ever known. I worked with him for seven or eight years. Everything else I learned from him has held up since then and I still believe what he said about oil as well. There have been some changes to motor oil over the years for sure but basically all of it is pretty good, just as he said long ago..

The Rotella oils have been around so long there must be billions of very successful miles logged using them. I probably have about a million miles myself between diesel AND gas. Someone (with a verrrry small sample size) comes out and says Rotella is no good for this reason or that and now suddenly it's no good. Really?  (That a rhetorical question. I'll have no further comments.)

edit: OK I lied. One more short comment. These days much of what you read (or  DON'T READ) from the manufacturers of all products is the lawyers talking. "We never said that" is just as important as "We said it's only for this" if they wind up in court for whatever reason, even if it makes no sense. They are doing what the lawyers are telling them to cover themselves prior to any trouble. Sign of the times.