I had a Mossberg 20 gauge with a pistol grip and 20 inch barrel for home defense, but it fell out my boat, along with several other weapons...worst day of fishing ever.
I am not a fan of the pistol grip shotguns. Even for home defense I want to line up sights or bead on the target. A 18” barrel with a stock that gives you the equivalent of a tactical LOP, and a light, works great. The pistol grip can smack you in the face if you try to sight in (granted 12 gauge more so than 20) particularly with slug or heavy buck shot. Its pretty much a shoot from the hip device, which works great inside of 10 feet or if you don’t have anybody or anything in the vicinity where collateral damage might be a factor.
I see the pistol grip Mossbergs in the store a lot, and a lot of folks buying them, but most of those I overhear really don’t know much about what they want or about tactical shotgun use, and the store clerks aren’t going to lose a sale in order to re-educate them.
I lost all my guns in a tragic boating incident, but then I moved to a different state and, miraculously, found them. :)