While we haven't quite fit this sequence of calibers to sequences of natural threat, I've had a lot of fun reading the answers so far. I guess a similar question goes as follows:
If you already have a good .357 and that's your most powerful option right now, does it make sense to invest in a .44 magnum or skip right to the dinosaur league?
If you buy a .460, you also have a platform for shooting .454 and .45. The .45 Colt is a comfortable sub-dinosaur round.

More importantly, the power spectrum it offers completely wraps the .44 magnum. On the other hand, it looks like going this route will lock you into lugging heavier equipment.