To the OP,
I have 0 experience with the Browning you mentioned, but quite a bit with the Beretta. The Extrema 2 is an extremely light recoiling shotgun. I don't find I need the oprional kick off system, with the possible exception of shooting turkey loads and slugs from a seated, static position.
I even have a few students shooting them at clays, and they run on light target loads just fine.
Keep in mind, the Extrema, like the 391 Urika and Tykneys, have a user adjustable system that lets the end user adjust for cast and height of comb with supplied shim system included with the gun.
Heck, I shoot a regular 391 Urika at waterfowl most of the time, and have not found a duck I can't hammer with 2.75" heavyshot, or a goose that can't be folded with 3" heavyshot. Its the address, not so much the package.
Either way you go, have a good season, and get out and shoot some clays before you go!
Best Regards,
Will Fennell
www.willfennellsportingpursuits.blogspot.com