I've had neither, but, the Zeiss has more flexibility and if HILL stalking you can put it at 6x and if WOODLAND stalking 3x would be ideal. I've handled an 8x56 but personally I'm not into "big" 'scopes and use two Zeiss 3-9x36 and a Zeiss 1.5-4.5x24.
Before that I used Zeiss 4x32 and 6x32 on my rifles. And a 6x42 Leupold on a .22LR for magpies and rabbits.
To my mind it's no contest save: Cost v the S & B; weight and length v the S & B; type of reticule.
And what cost premium you put on that flexibily. For low light, in theory 7x50 is equal to 8x56, but if you crank down a "power" 6x50 will be better...depends on if you need 8x or can make do with 7x or even 6x?
Twenty years plus ago we considered 6x42, fixed power, as the "ideal", "ultimate", foxing 'scope! No doubt the same "resident cretin" will be along shortly wanting to ask how many foxes I've shot this year.