Most people who try a pistol grip shotgun soon go to a full stock when they find out how much recoil there is and how hard it is to hit anything.
Contrary to Hollywood movies, you do have to aim a shotgun, even though it's actually pointed more than using actual sights.
Since a shotgun "cloud" of shot opens up about one inch per yard from the muzzle, in the typical house, you're talking about a circle of shot about 6 inches or so in diameter.
You don't just hold the gun low and point in the general direction or you'll actually miss completely.
Using a pistol grip shotgun is awkward because it's basically a giant two-hand pistol.
You can't aim it like a pistol, and there's no stock to use it like a standard shotgun.
Where the pistol grip shotgun is useful is as a "door buster" for SWAT use or for use by bodyguards from inside a vehicle.
Folding stocks are better these days because the designs are better. The old types like the Remington factory top-folding steel stock was horrible for pounding you with recoil.
A good source for stocks and other shotgun accessories is Brownell's.
http://www.brownells.com/default.aspx