It's not in a 20 IMO. I have this shotgun in 12 ga. and even at the light weight of ~ 7 lbs, It doesn't make a noticeable difference until one goes up the the 3 1/2 inchers.
The 20 should make a nice pheasant gun. Nothing against the Beretta but the Benelli Monty is lighter, less expensive, and a very good gun also. Plus in my view being an inertia driven action as opposed to a gas driven one, it's simpler in design (thus the weight savings) and a easier take-down.
But the A400s are nice too
