I agree with the others, if you reload go for the 454, if not, go with the 44. Or get into reloading
I reload for all of the above, 44Sp, 44 Mag, 45 Colt, 454, as well as 460. The 454 is more versatile. Don't kid yourself by looking at the BB loads, 454 is significanly more powerful than a 44. Shooting them out of a Super Redhawk is fun for about two rounds, then it becomes work. If I shoot more than one cylinder, I can feel it in my wrist for a while.
If reloading, all of these rounds can be downloaded considerably to make light loads. Lead bullets and Trail Boss powder makes for fun shooting.
Certainly nothing wrong with the 44 Mag though, one of my favorite rounds.