The difference between the cartridges set out in the question posed IMO may be academic as it is unlikely there is a cent's worth of performance differnece between any of them.

The real question here ifeel, is which is logistically the most readily available? Of course in the US as in the U.K ammo is avaiable from factory sources or Custom loaders, this is not necessarily so in most African countries, even .470 can be difficult to source in Africa, but some of the other claibres may prove even more difficult to locate. With the reanissance undergone in recent times with the .470, that, more than performance alone, may well be the raison d etre for selecting it.

Taylor noted over 40 years ago that there was little difference between any of the .450 - .475 class of rifles and that to gain significant advantage, .500 was the next power step up.

Ignoring the wild-cat magazine cartridges that have been spawned since the 1950's Taylor's comments IMHO hold good to this day, if you can be sure of a ready supply of ammo the world over for your chosen calibre then there is no reason to change.

Personally, I would follow the crowd and go down the .470 route, that said I didn't follow my own advice and went for a .600 instead