I will admit to never having shot or faced an elephant with a .458Win Mag but I have owned, used and reloaded for three, two belgian FN Browning Safaris and a CZ 550 Mag. Hornady Superformance factory loads are within 10fps of the .470 NE. Handloads with 450 gr and 480gr bullets give it an edge on the .416s at ranges it was designed for.

This guy likes it a lot.
https://bigborefan.wordpress.com/tag/battle-of-the-big-bores/