For me the difference is the additive package...though I can't say if that difference is worth anything.
Valvoline to me seems quite different in the add pack vs. the other major oil brands. Valvoline along with Napa, Shaeffer, RP, Lukoil, Peak, AZ, O'Reilly's, Brad Penn, Mobil 5000, etc. have lighter calcium and moderate sodium. And Valvoline per the PQIA results I've read has essentially no Moly or Boron. The only company I see that uses sodium and either moly/boron is Schaeffer. All the rest stay clear of Mo/Bo. I can only guess that Na plays a similar role to Mo/Bo in those other oils. Fwiw, I'm not a fan of heavy Sodium. I did run Valvoline conventional in my last oil change. Then shifted to PP.
I know others have said you can't judge an oil's performance by its additive numbers. I prefer to stick with the strong Ca, low magnesium, no sodium oils that also have some reasonable Bo/Mo levels....like those put out by Pennz-QS-Shell, some Mobil products like MSS/Mobil 1 0w-40, Castrol, Kendall, Havoline, Chevron, Citgo, etc.