I'll kind echo the others here, if you don't yet have a revolver, a 357 is probably the way to go. Ammo is much cheaper, full house 357 loads are still fun to shoot, and you can shoot 38s forever without any problems. Not so much with the 454. I have a Super Redhawk in 454(not Alaskan though) and with full power loads, it's fun to shoot, for about 3 or 4 shots, then it's work and it's painful. The recoil of a 44 mag is pretty tame compared to the 454. But yes you can shoot 45 Colts out of it, and those are fun plinkers.
I also have a BFR in 460, and that's another step beyond the 454. Lots of fun, and due to the mass of the revolver, it is actually less painfull than the Redhawk. It pushes you harder, but it doesn't have the quick snap of the Redhawk.
So if you already have a 357, and you really want that Redhawk, I say go for it. Especially if you reload. It really is a great round, but it's not for everyone.