People, you got me going on oil. I just can't help it. HELP ME, I need help!
Just another comment: there is a difference between an oil "meeting a spec" and being approved by the car maker. An oil may well meet or exceed a spec, and companies like AMSOIL (cherry-picked for no particular reason. I could have mentioned Red Line, Royal Purple, Lubrication Engineers, Primrose, Schaeffer's, Hydrotex, TRC, SWEPCO etc) are quick to point that out, but that does not mean the oil is car maker-approved. The oil approval process is lengthy and costly. It comes down to trust between the oil manufacturer and the consumer whether or not to trust an oil "that meets the spec" without approval.
As long as the vehicle is under warranty I would recommend to follow the car manufacturer's recommendation when it comes to engine oil. Once the warranty is up, you can more liberally experiment, especially if you know what to look for. Some oil companies, I am not naming names (AMSOIL

) give you an engine warranty. Uh, good luck?
With approvals it works like this:
Oils are approved by either ACEA (European Automobile Manufacturers' Association) and/or API (American Petroleum Institute). The specific ACEA and API ratings will give you a good idea of the type of oil and its performance envelope. API SN is the current rating.
The International Lubricant Standardization and Approval Committee (ILSAC) gives also out engine oil ratings that relate to the performance envelope. I think we are now at ILSAC GF6.
In addition, car makers have their own very specific engine oil requirements. After all, the engineers know the engines they build best. One car maker may have many different oil specs for different engines.
So what’s the difference? There are many factors:
oil for gas engines
oil for diesel engines (deals better with particulates), often also suitable for gas engines
energy conserving oil (friction-modified)
oils that limit certain chemicals (for example sulfur), which may affect some emissions systems negatively
oils have different minimum requirements for viscosity range, shear strength, viscosity stability (thinning/thickening), the capacity to neutralize acids (combustion byproduct), limits on piston and valve deposits and so on and so forth
suitability for extended drain
etc
Tribology (lubrication science) is pretty complex and it’s really best to stick with the car maker’s recommendation. However, I have to say that car makers do change their recommendations over time. For example, there has been trend in the industry to go with lower viscosities that befit fuel economy. For example, Ford has been for years recommending 5W-20 for many engines, including the 6.2L V8 and 6.8L V10. For 2016 they have changed the recommendation to 5W-30. Is that because they got warranty claims form engines that wore prematurely on 5W-20? I don’t know and Ford doesn’t say. The thing is, all car makers have to meet CAFE (Corporate Average Fuel Economy) standards. One of the way to that is to lower friction in an engine by using lower visocoty oil. Of course, l.ower viscosity oil can, under certain circumstances (high oil temperature, increased pressure on friction surfaces/in bearings) result in increased wear.