Guys, I can help end the argument for you. I will take some Stihl and other chain to the materials science lab tomorrow and test the hardness out using our hardness tester.
BUT , . . . . . . Hardness is not everything especially as far as wear is concerned. Wear also depends on Toughness and a whole bunch of other properties. Think BIG, like the blade of a bulldozer. If the blade was carbide hard the blade would chip and crack and bits would break off in no time. A tougher material might even be a bit softer but will crack or chip less so at the end of the day the remaining edge might still be sharper. Any given material compared to any other material may also have different wear characteristics depending on whether the wear is against a material harder than itself, the same material as itself, or a material softer than itself.
So the chain with the better holding edge might in fact be softer but tougher.
BTW, I reckon when filing, stihl is about the same hardness as orgeon and both are softer than GB chain.
Cheers