One perk is that there probably isn't an easier caliber to find ammo for.
That said I want a .270, still big enough to do about anything with, pretty common to feed, and they shoot a little flatter.
Right now I am thinking about whether I want/need a .270 100ATR, 12ga Mossberg 500 slug gun or a 1875 Remington clone .45LC pistol. The .270 would be lighter to lug around than my Mosin and far easier to find ammo for, a fullsize 12ga shotgun would be nice for deer hunting, but then a cartridge pistol would be nice for deer hunting...
For the moment my Mosin, Bantam 500 and 1858 Remgington do work though.
Everybody makes noise about how much a Mosin recoils, even with a plastic stock it is nothing compared to my 20ga slug gun.