Well, it took me an hour and a half, but I got through the whole thread. LOL
I've owned several types of shotguns over the years. Some are more fun/comfortable for me to shoot than others. My current favorite is the Saiga 12, but that doesn't mean it's what I choose for HD. Yeah, the Saiga is very fast and I'm able to use it fairly well, but I still look to my Mossberg pump for home defense. Fairly minimal on accessories too, not like the Saiga.
I have a little bit of a special consideration when it comes to what works for me and what doesn't. 25 plus years ago, while in the Military, I received a 12 ga wound to my right palm that took out the wrist and part of the forearm. My hand was touching the muzzle when it fired (attempting a disarm on a BG). They were (miraculously) able to save the hand, though I have limited use/grip. Being right handed, I had to learn to do more stuff with my left hand, including shooting.
With a fused right wrist, I almost REQUIRE a pistol grip stock if I'm going to attempt shooting with my right hand. Otherwise, I'd just have a finger or thumb inside the trigger guard without having a hold on the stock. So I tend to fire things left handed. Of course, this makes getting a good grip on the forend difficult (hardly any strength in right hand). I'm looking at a pistol grip on the forend, but haven't liked any of the ones I've handled yet. I'm open to suggestions.
Reloading for me is typically done with my "strong hand", though that may be against most instructor's teaching. I end up dropping more shells trying to use my offhand to load than anything. I do OK handling magazines with my offhand, but that's more for rifles than shotguns. As I mentioned, I enjoy shooting my Saiga 12, but I don't know that I'd be prone to grabbing a couple extra mags when I hear something go bump at 3AM. So my Saiga stays in the gun safe.
My HD Mossberg started out as the 500 breacher PGO setup, but having used a PGO shotgun before, I wanted to change that out ASAP. The breacher 500 reminds me of the 590, in that it has a thicker barrel and the 590 style magazine cap, only it's in an 18.5" length. Just an observation.
I added a +1 choate mag extension and "enhanced" safety tab, as well as velcro on the left side to accept a "side saddle", though I typically don't have one mounted. Still debating a weapon mounted light. It currently has a pistol grip choate (I think) stock on it. Without going to a folding stock, I'm not familiar with any other stock that also has a PG on it. Suggestions? I'd be willing to go with a folding style, though I doubt I'd ever have it folded. LOL
Thanks for the informative thread.