Atmat nailed it. Within each family of guns, there really is zero difference other than the embellishment. Personally, I would MUCH rather have a plain-Jane action without engraving, and spend the money on getting the right fit. Same thing with guns with side plates, it’s nothing more than embellishment, it has absolutely zero impact on function whatsoever.
It’s been a little while since I looked in great detail, but rizzini and guerini are/were basically the same action. Beretta‘s are slightly different, but also fairly similar. All of these Italian over and unders are a similar design, it’s a little bit less high of a receiver than the old Brownings used to be, little different lockup, but they’re all very good. Things to look at are whether the action is a dedicated size for your gauge, or if you’re getting a 28 gauge on a 20 gauge receiver, a 20 gauge on a 12 gauge receiver, etc. Sometimes you wind up with a slightly heavier gun as a result, but it gives you options for multi gauge barrel sets, etc. so pick your poison based on your needs. Sometimes the 28 gauge ends up weighing more than the 20 in these cases, because they have to build the barrel lugs larger in order to fit in the larger action so you end up with extra weight on both parts. In this case, I don’t know why people bother with a 28 gauge, but if you’re into it it’s an option. Other things to look for are stuff like replaceable trunions so if you get into shooting a ton of clays and it wears out after 100,000 rounds, you can simply replace a part. Most people don’t end up needing that, but it’s something that can help resale value, and it’s not going to hurt at all.
Regarding an aluminum action, I greatly prefer a steel action. The entire reason I say that is from a handling perspective. On a 20ga you save 5 or 6 ounces in gun weight, but it doesn’t really affect the handling of the gun hardly at all because all of the weight at the ends of the gun, the butt and the end of the barrels, is still there. Out at the ends of the gun, all that weight is effectively on a lever, so you notice a few ounces a lot more. The only place you actually lose weight with an aluminum receiver is between your hands where you notice it the least. But that weight comes at the expense of shoot-ability and recoil. Regardless of whether you’re getting a 20 gauge or 28ga, I would look for something right around 6 pounds, maybe 6 1/4, depending on how you’ll use it and what type of hunting you’re doing. Lighter than this is far more difficult to shoot consistently, and I don’t think really makes such a big difference in carrying it unless maybe you spend all day with the gun in one hand, parting poplar whips with your other. That 6-6 1/4lb weight is easy to achieve with a steel frame 20ga, so I think it results in a better handling gun overall. One of the best handling 20 gauge over/unders I ever used was a Perazzi with 30in barrels, that gun weighed almost 7 pounds but it carried and handled significantly better than guns weighing close to a pound less, simply because of where the weight was distributed—all in the action, with very light fixed choke barrels.
My money buys the one with the most plain-Jane blued receiver, because that’s what I personally like visually, with a custom-fitted stock, and the lightest 30 inch barrels I can find. I would personally take fixed chokes over choke tubes because the barrels are generally thinner and lighter, but that’s hard to find these days. But I would 150% take a less fancy gun in order to get a fitted stock.
