If you ever go to any lubricant blending plants, like Shell in Brockville, Ont, or Petro-Canada blending plant/refinery in Mississauga, Ont, you'll be very surprised to see how so many brands come out of the same pipe in the bottling plant..
All engine oil (without exception), whatever the label, the bottle and marketing claims, and meeting the same API specs are basically equal in quality.
A 10W40 API SM is a 10W40 API SW, whatever the make or brand it is.