I'm not going to recommend one over the other for deer. I've had both and found them equally capable. When you get into bigger game the .45-70 will have an advantage, but deer?, either/or.
It would come down to how much weight you'd like to haul around, the .44 generally being lighter, both ammo and rifle. With that out of the way, I recently sold my .44 rifle, but it had nothing to do with the cartridge/rifle vs .45-70, but instead of simply having too many rifles....
