Back in the mid 70s I saw that the 458 was the "standard" in 3 Africa countries for game control officers and most professional hunters. Seems all the complaints I ever heard about it were from Americans and never a one from an African hunter.
A 45 caliber 500 grain bullets at 1950fps to 2100fps seems to do what it needs to, and today the better powders and better bullets make it all that it should be and probably more.
I was young then and the light American made M-70s seemed to kick awful hard, so I used a heavier and less powerful 404 Mauser, but all others that used the 458s never seemed to have a single complaint about how well they killed game.
The 404 did everything I ever asked of it perfectly. So I have no doubt the 458 is going to do it all as well or better. If a 400gr 42 cal at 2200 is good, how could a 45 cal 500gr at 2100-2200 be bad, if both use bullets that don't fail?

I personally never used the 458 on African game, but I have seen them used and I know a lot of other men that used it. I never saw or heard of a problem from anyone who I knew personally and other than a few magazine articles I read at one time or another, I have not heard any complaints.

I would have no reservations at all about using one myself.