JR,
Just noticed from your post count that you are new to the forum.
Even though you're getting a baptism by fire, I would like to say a belated "Welcome".
There have been many threads comparing the 45-70 to the 458 Win Mag, some making outrageous claims for the 45-70 of superior penetration and exaggerated suitability for dangerous game, so this is one of those topics that bring out strong reactions from those that post here.
Hope your rifle turns out well and suits your needs.