Any SG with only a PG is pretty close to useless except for across the aisle distances. Folders are more practical when short OAL is paramount, like in a cramped vehicle or aircraft, for the getting out of, and then extending the stock.
I am an advocate of regular stocked shotguns for a couple of reasons:
1. You want both hands in the same plane, not at right angles to each other for best weapon control.
2. The same for both weapon rentention(shotguns are close range weapons), and using the weapon for the vertical/horizontal butt stroke so beloved of drill sergeants prior to the M16.
3. With slide actions guns, I seem to be able to control the pumping action better with a standard grip stock. Having a pistol grip on the forearm of a pump may be neat looking, but essentially useless due to the hand angle, couple it to a pistol grip for the firing hand and you have got even less control.
There may be a place for the so called "witness" type guns with 12" barrels and a modified pistol grip, but it is an absolute "belly gun", and less useful than a handgun at anything over 3 meters.
I have carried shotguns professionally for 40+ years, and if you look at what the real pros carry, you will see pretty much a plain jane weapon without, saddles, lights, lasers, glass packs, rocket launchers, JATO units, etc. What you might see are ghost ring sights, extended mag, maybe even a holo sight, a sling, and every so often a butt cuff w/5-6 extra rounds.
I am not intent on deingrating anyone who wants the extra tactical stuff, but aside from looking neat, most of it does not add appreciably to the utility of the weapon. In some cases, as in recoil operated semi auto guns, the extra stuff will interefere with proper functioning of the weapon. That said I have 2 (out of many) shotguns with a full stock with an "assault type" pistol grip, both are 1100s, with long barrels and 9-10 shot mags, and are specific purpose weapons, used primarily for defending a fixed position against a known threat where the distance from the position and nearby cover/concealment is really short.
I have Hogue stocks on a couple of 870s, and really like them, only snit is the LOP is slightly long for real tactical use, but for recoil control and "grippiness" they are really nice.
IMHO, the "speedloaders" are useful only in matches, I have a few, but the carrying and use of in a real life scenario are probably not practical.