I had my 7 1/2" and 9" .475's 4-ported, and I scoped them, as serious hunting guns. My 7 1/2" .454 is also 4-ported and scoped. I've hunted a good bit with all of them. Personally I prefer that 6" barrels or shorter remain unported, and all but one of mine are.
I believe that porting does reduce muzzle climb, as does the weight of a scope and rings. However, 2 friends and I did quite a bit of testing on 3 FA 7 1/2" .454's about a dozen years ago, and found that with that cartridge, a ported gun will lose about 100-125 fps vs. an unported gun, depending upon the load.
My own objection to ports on the shorter barrels is more related to aesthetics, and muzzle blast / debris through the ports, though, than to velocity loss.
I'd buy a flower carved holster instead.