Unless you are going hunting then you have no real legitimate reason to buy it. It was designed as a hunting revolver, with a hunting cartridge, and not as a target gun. There are plenty of other choices for a dedicated paper puncher, carry gun, and bear gun(not the 8' models in this regard).
I had done a bit of research between the .460 and the .500 before I ended up purchasing a .460. I will explain my reasons for such.
My reasons for buying it were that I needed a lightweight, compact alternative to the shotgun that I was carrying around with me. I was stalk hunting at that time so weight was an important consideration. It excelled in that role, but if you ever fire it then you must make sure you are aiming to kill with the first round, the sound after the first shot will scare off anything else. Accuracy is great with it, but by far better with a scope attached, which I would have to say is a necessity. The original 8" models, both .460 and .500, were designed to take their rounds out to 200 yards with deviation in the inches(lesser length models still retain this, rough calculations will figure 100 yards for a 4" model as it is that predictable). I expect that with the cost effective need for handloading/reloading you would see a significant decrease in deviation as well. A scope is pretty much mandatory to effectively use both calibers at the 200 yard limit they were designed for(they can always go past that limit with the right amount of fine tuning).
Now the caliber switching in the .460 makes it a very cost effective solution. Usually factory .460 ammo is in smaller amounts at gunstores, and other places that sell factory ammo, then say .45 Colt, Long Colt, or .454 Casull. You must look into making your own supply for this gun, while still maintaining the ability to buy off the self ammo at most places. Certain reasons would be if you were in a new location hunting, and you didn't have any rounds made from your own recipe, you lost your ammo, etc. You need availability at almost all times so the .460 has a plus over the .500 in that department, but I will add that I have seen more factory .500 ammo then I have .460 ammo.
The plus for the .500 is that you can currently load your cartridges with higher grain bullets for hunting larger game then what could be used with the .460. With a scope, and your own loads you could take a round and possibly kill almost any game animal in the world. It' not an exaggeration to think that. Casting your own bullets is also the best cost effective solution. You will pay quite a price for the molds up front, but the amount you will save just with the first batch over a box of factory ammo will be amazing. The molds will pay for themselves very soon if you keep casting them.
Now the velocity/muzzle energy charts between both calibers is even is regards to one round(when I researching this before my purchase several years ago). That round is the Hornady 200 gr. flex-tip(The one the marketed under the Lever Revolution name). The data for both calibers was the same as far as that one round, and that was nearly the same same for both calibers. Outside of that you will see higher numbers in muzzle velocity for the .460, while you will see higher muzzle energy for the .500. The only time the numbers will be similar is with that one Hornady round. I firmly believe that round is that best all-around round for any type of hunting for anything up to a large 300 pound hog, and including some small black bear. It will take deer easily, and it will take your almost typical 100 pound hog with ease, with proper bullet placement of course. I also think this round is the best even if you were to spend a day at the range. The recoil is negligible with this round. I recommend that if you do load your own, and make your ammo, that you find and make as many carbon rounds as you can, and improve on Hornady's recipe as soon as you can.
I also need to state the hearing danger of the muzzle brake, and tell you that you will need to purchase and carry hearing protection with you everywhere you intend to fire either caliber. There are non-ported models in the .500 caliber, but there would be an increase of recoil. As was stated above a blank muzzle brake would be nice, but aside from having it specifically machined, they are unavailable, and the last people to do a production run was S&W themselves before shutting it down, due to unknown reasons.
Some of the info I have said has already been said above, so I am just reiterating the importance of that info if it comes to it. Ultimately you will be the person who decides on what to buy for yourself, so make sure you ascertain, and list your own needs for yourself rather then spend, and lose money on something you will eventually sell for a lower price than what you paid.
Simply put, if you are not going to hunt with either caliber, then don't bother at all. If money is an issue, or will be, and you are also going after just deer, then just go with something in .44 magnum, maybe put a scope on a nice Ruger.