Ive got a Benelli M1S90 Tactical with the pistol grip stock, and I also have a Benelli Super Black eagle with the standard stock that is my waterfowl gun. Since the stocks are interchangeable, Ive switched and played with both. To me, the pistol grip is steadier on things Im aiming at, while the standard stock is better for things Im pointing at IE wing-shooting.
The pistol grip does allow the gun to be used easier one-handed, and it seems to make the felt recoil a little less. It also allows you to pull the stock up under your arm and shorten the OAL for opening doors etc.
Id try both, and then make an educated decision.
Chuck