In a Handi, a 45-70 can do anything the 450 Marlin can do - and then some with the slightly more case capacity. ...and do it cheaper.
If you reload, 45-70 brass can be had for much less then 450 marlin. If you buy boxed ammo, same thing.. Although none of the big ammo makers make Marlin/Ruger #1 loads - keeping pressures safe for people that think a Springfield Trapdoor can handle anything. With the blessing of the Handi, Marlin Lever guns, and Ruger #1's - Buffalo Bore ammo can take anything that walks on Earth with the 45-70.