I have both. The 45/70 because I wanted it and the 30/06 because the Remington/Spartan is discontinued and those are the two calibers - they aren't going to do anything but go up. 45/70 ammo may be a little more expensive but 30/06 isn't cheap. 45/70 has more brushbusting "poop" at double rifle ranges while the 30/06's longer effective range is pretty much wasted. Both can be downloaded to plinking rounds and one can even go "old school" with black powder 45/70 loads.

One advantage of the 30/06 is that extra pound of weight. Add Remington "Managed Recoil" ammunition and you have a light-recoil close-range "whitetail whomper" for Momma, the Boy or even Grandpa.

They say the 45/70 is regulated with factory 405 gr softnosed bullets. That is probably the one 45/70 you can be pretty sure to find anywhere.

My $0.02 worth.

Tom