Briman,
You're right about the 8 x 57 brass and it's price and availability now..........but in 1945 availability and resulting price of 8 x 57 brass was a different story. And Berdan primed was all you could get (then). But it was that scarcity of the German ammo that gave birth to the 8mm/06.
Now, as you say, 8 x 57 ammo including new, surplus and components is available and affordable.
Nothing wrong with shooting available surplus today.......and I shoot bunches of it year round.........but only b/c the price is good now.... and has been for the past 15 years.
Shooting modern factory loaded 8 x 57 is a joke.......it works, but you lose a bunch of potential. Handloading is the way to go for both the 8 x 57 and the 8mm/06. And I always have fresh, loadable brass from my Savage 110 in 30/06.
I have a couple 8 x 57 mausers (a German and a Turk) and my dad has a European sporterized Czeck 98 with only a peep,... but it drives tacks.
I think the difference between the 3 rounds, the 8 x 57, 30/06, and the 8mm/06, isn't very different at all. They are all excellent rounds................it's nice to have all 3 though!