Never shot the .450 marlin, but I own 4 different H&R/NEF guns, and I like them all. The .450 is basically a "hot rodded" .45-70. However, if you don't handload, the ammo available is more limited than the .45-70. If it were me, I would get an NEF handi rifle in .45-70, and if you want the prettier laminated stock, order one for it from the factory. If you want more info about their rifles, look up H&R talk in your search engine, and go thru their forum threads. There is a wealth of info about their rifle and shotguns there.
Mad Dog