Well, I like my rifles chambered for 7X64mm Brenneke because the cartridge was developed for bolt action rifles from its genesis in 1917, and the factory barrel twist rate of 1:8.7 inches. It doesn't make it "better" nor "worse" than .280 Remington but it's better suited for my uses of a 7mm cartridge with a 63-64mm (standard long action) case length.
It's opposite directionally for me, liking my 7mm-08 rifles more than 7X57mm. There's a wider array of factory ammunition and their 1:10 inches rifling twist rate is fine for projectiles as long as the 160 grain Accubond which is reasonable to load without excessive intrusion into the powder column section of the X51mm case. That's where I see my 7X64mm rifles showing their differentiation: 160+ grain projectiles which are longer as well as heavier. But I don't see 7mm-08 as either "better" or "worse" than 7X57. It's a better "fit" for me in my philosophy on how I developed my personal accumulation of rifles.
I've heard tales of hunters who had BAR's converted to use 9.3X62mm cartridges. Certainly not for wide use outside the USA with semiautomatic rifles not being allowed for hunting in many other countries. I haven't personally met anyone who did that yet.
