I vote for the 45/70 because
1 there is so mutch loading data out there from a light cast going slow for plinking to marlin 45/70 loads that can take anything in north america
2 if you need to buy ammo in a pinch it is a lot easer to find
3 I am bias I have 3 and am working on a 4 but both cartregs can be loaded close to each other
4 I saw the remains of a early marlin 450 that had been shot less than 60 times with factory ammo , shooter just got scratched up thank god
5 and yes I have used the 45/70 with great results