Of course it depends on the rifle but the recoil of the 450 Marlin with a 350 grain Bullet at 2200 fps is 37.2 lbs. About the same as the 375 H&H. Also about the same as 45-70's loaded to that level. While these nunbers don't tell it all, it does tell you something about the 45-70's ability to recoil. Factory 45-70 loads recoil at about 17-18 lbs.
I agree. I have a .450 Marlin and a buddy of mine shoots a Ruger #1 .375 H&H and he refuses to shoot my .450 after he shot it once. I have trouble shooting it now because I shattered my wrist last year and now I have to shoot it left handed. Though when you hit something with it you don't have to worry about having to track it down.