I've been pondering the purchase of a 454 for quite some time now and have considered both you mentioned. I agree that the Ruger will probably hold its value better than the Taurus, although I am partial to Taurus'. FWIW, I have a friend who bought a slightly used 454 from someone he knew who bought it, put less than a box of ammo through it, and then sold it due to recoil. He saved a lot of money by going the used route. Look around; you might be able to pick up a used one for a good deal.
Whichever you decide, please post a range report and let us know how you like it and info about any handloads you use with it.