I guess it depends on what you are going to use it for. If you are after the biggest and baddest of game, I'd narrow the field to the 475 and 500. If you want practicle, the 475 has less expensive brass, and bullets are more common, plus you get to also chamber my favorite round, the 480.
But, if you have to have the biggest Linebaugh, and something bigger than the 500 S&W (by all of 0.012"), then the 500 is is.

I've shot several 475's and 500's, and they are both quite a handful with top loads. Performance wise they are also pretty much equals.