EdInk, the 44 Mag is in a different class than the 480 Ruger. For example, considering standard loads, the 44M propels a 240 gr bullet at 1,180 fps while the 480 with a 275 gr bullet develops 1,450 fps. Respective muzzle energies are 740 and 1,280 with muzzle KOs of 17 and 27. And the 480 produces about 160% of the momentum of the 44M.
The 480 is closer to the class of the 454 Casull, which develops 1,800 fps with a 260 gr bullet for a ME of 1,870 and a KO of 30, with almost identical muzzle momentums. At the top end (e.g., Buffalo Bore and Grizzly) the 480 develops a slightly higher KO (35) than the Casull (33) because it's propelling a larger diameter bullet, while the Casull will shoot a little flatter due to the higher velocities. The 480 can also manage a 425 gr bullet (putting it in the 45-70 league) while I believe the heaviest bullet available in Casull is 360. That's a big difference when hunting the largest game or defending against a Kodiac. That said, for most purposes the differences are pretty minor and will be far outweighed by the shooter's skill and circumstances. Which is probably part of the reason why the gun wasn't the success Ruger had hoped for.
I own both and I'd say if you were to own one, pick the Casull simply because it also shoots 45 Colts while there's no "light" load available for the 480. My Casull is a Ruger Alaskan with a 2-1/1" barrel meant for up-close defense against surely animals while my 480 has a 9-1/2" brl and a scope (on order) and is meant for distance shooting and hunting. Part of my attraction is the odd-ball nature of the 480, the underdog status so to speak. And it will probably appreciate in value (though Ruger has officially "suspend" rather than cancelled this gun and there are rumors that they'll re-issue it when inventories are sold, but with a 5-round cylinder (mine holds 6). Since it can also shoot the 475 Linebaugh and chamber pressures are within spec on the SRH, there's also rumors (perhaps hopes!) that they'll issue a 475 L cylinder for it when (if) they start production of the 5-round version. I'm part of the "hope" crowd.
The 460 s&w is in yet another class. Factory rounds develop MEs of 1,300 to a whooping 2,860 ft-lbs while KOs range from 30 to 45. And the 460's trajectory is the flattest of the bunch because of the stellar muzzle velocities (2,300 fps with a 200 gr bullet). The 460 also wins on versatility, accepting Casull and 45 Colt cartridges. Mine has an 8-3/8" barrel and is a fantastic piece of machinery.