I picked up a couple Mossberg 590 20" Persuaders for $240 each a few years ago at WSS. Lighter barrel than 590a1 - has a heat shield.
It is all parkerized - keep it oiled and you are good to go.
Not sure if you really have to worry too much about bears these days though...
My preference is the 590 Mossberg as well; while I'm of the opinion that the full length magazine tube is of little benefit, the benefit realized from the Magpul SGA buttstock makes it a good investment. It is prudent to swap out the steel follower for a nylon one, as the steel follower can rust to the magazine tube is the gun is exposed to wet conditions for a period of time. More important than the long magazine tube, is having the ammunition in or on the gun that you need to resolve the problem. A sidesaddle provides the means to have a different type of ammo from what's loaded in the magazine, instantly available, and I'm happier having the trigger group secured with a bolt, rather than a pin. Additionally, the sidesaddle doesn't prevent shooting from your support side like a butt-cuff does.
One often hears the advice to load different types of ammo in a specific sequence, so the order of loading runs something like cracker-buckshot-slug. That's all fine and good if a threat, that must be resolved with gunfire, occurs in the way you expect it to, but if you step around a rock and are faced with a dangerous bear, having a cracker as the first round doesn't help much. Conversely, if a family member is in danger, and you're 50 yards away, your role is diminished to that of an oberver if you have a cracker or buckshot in the chamber. My preference is the magazine tube loaded with slugs, and the chamber empty. The gun can then be cycled for a slug, or single loaded through the ejection port if a different round is required. If you prefer, load the gun so magazine has room to add a select round, you simply load the select round into the magazone and cycle the gun normally.
An oiled gun is a mixed blessing, if the gun is leaned against a rock and falls over into loose dry sand, that'll be the moment you need it, and to say it will be difficult to cycle understates the problem. Better to have the gun clean and dry, then it is to make it less reliable under certain conditions by having it damp with oil.
I think we have a difference of opinion when it comes to having to worry about bears these days. What makes these days different than previous times, is that there is more human encroachment into bear habitat, a greater number of habituated bears, and a significant segment of the public that doesn't respect a very successful large animal, preferring the Disney version of nature to reality.
My 590 with it's Magpul stock . . .
A potentially deadly situation, the bear is on a carcass in the rocks, during a heavy rainstorm . . .
This is a nice sequence, notice the bear approaching from behind the rock further along the coast . . .
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