I own a 450/400 3 inch double rifle. I voted for the 450/400. That being said, if I were to add a double to my collection, I have a 9.3X74R and a 8X57 RJS, it would most likely be a .303 or even a 30-30. Especially, if all you were going to hunt was North American non-dangerous game.

I would have a .303 any day over a .375 Flanged. I think the .375 Flanged is way under powered.

My least favorite double is the 9.3X74R. I do most of my hunting with the 450/400 and 8X57RJS.
Recoil is not an issue with a 10 pound 450/400.

With a new 450/400 you can shoot traditional 400 grain Woodleighs, Hornady DGX & S, Hawk, and 405 Winchester 300 grain bullets.

Just my opine.