Rifleman,
I still have the 45/70 but parted with the 450 because it was just too loud with the porting, I got rid of the others because I moved from the east coast of Australia (Victoria) to Western Australia, and the gun laws here in WA are ridiculous and it was too much trouble to take them with me, also availability of ammo and brass for the 450 was hard to get hold of here, where as 45/70 brass is quite common and readily available from interstate, I think if we were only aloud one rifle and calibre here my choice would be the 45/70, purely for the availability of projectiles, case life and knockdown power, not to mention the handiness of marlins guide guns configuration.
I aslo have two 458 Lotts it makes it easier for buying in projectiles, we are 1000 miles from the nearest gunshop so we have to think well ahead in terms of reloading supplies.
Hope this answers your question.
Chris