Late to this party, but I'll comment anyways...
A disclaimer first - my first shotgun was a Winchester 1300, to which I killed many pheasant, spring gobbler, and even some grouse. I even competed with for many years in "junior" matches. I won many, much to the chagrin of many a rich teenager and their fathers. I have since owned dozens of shotguns and have roughly a dozen now (if you include the SxS's that I only take out once a year for dove hunts). My current HD gun is also the gun I use for 3-Gun - a Benelli M4 with extended tube and field stock.
Here's a pic of my 590A1 - a gun that I got on the cheap and use as a backup for hunting, camping, range work, etc. No chokes and cylinder bore and I can still hit a 12" target at 100-yards with the ghost-rings and Remington Slugger's.
There are pros and cons to both the guns in question. I currently have both an 870 (two actually - one with a 28" bird barrel/20" Rifle barrel combo and the other that is being turned into a "He-Man" gun for 3-Gun competitions), a 590A1, and a 590. Each gun has its benefits but I prefer the Mossberg for HD (and also for someone getting into 3G). The 590/590A1, though very heavy will mitigate recoil better than the 870. This is very "general" and model dependent, but I'm a big guy with a lot of shotgunning experience and I can notice a difference in muzzle rise between the "base" models. A heavier shotgun will indeed have less recoil. Thousands of shotgunners and F-Class shooters around the world add weight to stocks and forends for this reason. However, "perceived" recoil is person dependent and for those that have noticed heavier guns beat them up more, it is likely due to fitment issues - not weight. Everyone at one point in time should have a shotgun stock fitted to them. This can make a 10-gauge feel like you're shooting a 20-ga and makes high-volume shotgunning much more enjoyable.
The ambidextrous safety of the 500/590 is a big selling point as well, particularly if you're a southpaw shooter like I am. Another advantage of the Mossberg is the loading gate stays "up" and out of the way during reloads. Anyone who has loaded a Remington or Benelli quickly and ended up in a bloody mess can appreciate this feature. The capacity of a 20" Mossberg is also greater than a similarly sized Remington and disassembly of the Mossberg is truly "tool-less". The Remington with extension will have a magazine clamp and requires an extra step plus a screwdriver to remove the barrel.
Another benefit, though probably not important to everyone, is that the heavy barrel of the 590A1 can easily be tapped for chokes, where the 18.5/20" Remington barrels cannot. The reason that the Wilson guns and others are so expensive are from both the "Wilson" engraving on the side and from the amount of work put into the barrel. IIRC, Wilson cuts down 28" barrels, removes the vent, back-bores, installs chokes, etc. This will run you about $175-200 for a good smith to do this work.
The Remington has the advantage of being able to be made into "multiple" guns quite quickly. I can take my 28" bird barrel off, put the 20" rifle-sighted barrel on, add a +3 extension, and have a trusty and reliable HD or hunting gun in less than 2 minutes. The 590, due to the barrel retention design, will always be a 590. The 500 is more "adaptable" but the design limits the ability to easily add a magazine extension. You could turn a 500 into a viable HD gun, but converting back to a gun for hunting requires a lot of work.
As always, YMMV and you should pick the gun that appeals to you the most. If this gun will be mostly a HD gun, then be sure to pick options and models appropriately. You don't need ghost-rings to shoot slugs accurately to 50-yards (3-Gun guys do it all the time with a bead sight). A pistol grip, saddle mount, etc. are all good to have if they work for you and are appropriate (though a pistol grip on a 590 makes using the safety a challenge). FWIW, I picked up the 28"/20" combo mentioned above for $300 and it UNFIRED in the original box with wrapping (see below for a pic on its first dove hunt). This is an older "Express" model that still had the steel extractor and metal trigger guard. I picked up another older Express (no MIM or plastic... not that it matters really) in great condition for $265 (the gun that I'm turning into a He-Man gun).
Alternatively, you can just say f&$% it and get a Benelli M4
“Knowledge is knowing that a tomato is a fruit, wisdom is not putting it in a fruit salad” -Miles Kington