Not long ago I aquired a GSG 1911 too. It's surprised me in many ways. It has been reliable, very accurate and has a pretty good trigger. So far minmags are all I've shot through it. The manual stipulates HV ammo I think.
I also have a relative of your Beretta... a model 948. Except for the tiny sights, this is always a pleasure to shoot. This gun feels very good and produces lots of smiles.
My ultimate favorite .22 though has to be a third gun I own, a Daewoo DP52. It's as hard to find as a nice Beretta 22 and made just as well. Very reliable, nice sights and accurate as they come. A great addition to any fun .22 collection.