airshaq20,
I'm no "expert" in oils but i do my reading and use lab results. Have you heard of used oil analysis? I have my oils analyzed for viscosity, TBN, wear metals etc. which gives an unbiased snapshot of what's happening in the engine.
You can choose a viscosity based on lab tests after you benchmark the OEM oil.
Why go back to mineral from synth oil? Well, my synth oil soot levels were high at 6k km intervals so it was better to change more often with mineral.
I've used Mobil 1, Delvac 1, Conoco synth and others- most subjected to an oil analysis.