DaleA said:3. The on going expense of hiring a young lad or laddette to carry the thing around for me. ("Oh gun lackey! My .500 please, the rhino seems to be charging!)
Kidding aside I'm more than a little envious but I'd prefer the big X-frame in .460 for the versatility.
The 460 is definitely more versatile and cheaper to shoot. My 12 year old "laddette" (granddaughter) won't touch the 500 but loves shooting my 460 with 45 Colt's in it, recoil is about like a .22, although she needs a tripod to hold it up!