I bought a Benelli Montefeltro this past season for ducks. At ~5 lbs I believe it is one of the lightest 20 ga waterfowl guns you can get, made everything else on the gun rack feel like a brick.
While it is a dream to carry and lightning to the shoulder I cannot get used to the rib. It is a flat rib flush with receiver designed to shoot just above the front bead (unlike raised rib on M2, SBE, etc.). I just can't get used to seeing the top of the rib, and it hurts my shooting. With my 870 I am used to covering the bird with bead, Benelli wants the bead to be right under.
It seems like such a small detail but its soured my desire for this gun. So if looking for a new shotgun make sure you understand difference between flat/raised rib, I did not....