It strikes me as odd to ask for opinions after you've purchased it, especially with that many rounds already fired. But, since you haven't had much other shotgun experience to compare it to, it is a practical question.
I bought an M4 only because of my history with Benelli on the other models, especially my long time love affair with the SBE 1 (H&K import). I fell in love with the inertia action. Personally, it is the inertia action of their semi-autos that IS Benelli to me. But, the M4's gas system allows it to be softer recoiling, and offers some "freehand" (meaning firing without resistance) shots that will cause the inertia models to eject and close on an empty chamber. With the US military's interest in the M4, I think that caused many in the states to give it a look. The M4 models have a ton of aftermarket parts if you are of the type to personalize them to a hilt. On that topic, remember that if you start replacing parts, make sure you are following the 922r laws. When the M4 is fully "kitted out", they somehow manage a modern classic look for us older shooters, while still being "tacticool" for the younger generation. It probably doesn't hurt that it is featured in most modern video games too.
As to why I got into Benelli in the first place, I used to have a different shotgun for different seasons (upland game, waterfowl, dove, skeet, sporting clays, trap, etc). The constantly changing guns meant that with each season change, I missed some shots until I got the feel for that particular gun again. I first read of the Super Black Eagle in 1994; that it could shoot 2.75", 3", and 3.5" mag. In any order, and without adjustment. I made a 3 hour round trip to a gun shop that had one. After holding it, the balance felt good, it was lighter than most of my current guns, many which were only 2.75". So, I saved up about a grand which took me quite a while. So, in '95 I brought home an H&K import Benelli Super Black Eagle. The more I shot it, the more I liked it. So, I slowly started selling my O/U's (Browning Citori and Ruger Red Label), then sold my SxS, then my pumps including the two you mentioned (I do wish I still had the Ithaca 37 for my left-handed friends to shoot), then lastly sold my Ithaca. So, for ~10 years I had ONLY the SBE; well, and a .410 1100 Remington that I traded for that is mint. During that time I bought a rifled slug barrel and modified forearm (required for the SBE 1 to shoot the slug barrel and/or for later field barrels). I said at that time if some atrocious law came into effect that only allowed us a single firearm, that would be it.
Flash forward to now. I started to collect them some years back. I now have an M1, two M3T's (top folder's), Montefeltro 20 gauge (my wife's clay pigeon gun), two SBE's and every factory length barrel that was offered (24", 26", and 28" in both low rib and high rib barrels, plus the aforementioned slug barrel), an all black modified M4 (these are gas operated), and the rare and valuable M4 H2O (NP3 version) model 11711.
I liked Benelli so much that to this day, only other shotguns I still have only the Remington 1100 .410 and a Savage 22/.410 O/U that I've had for 25+ years. However, a Franchi SPAS-15 or SPAS-12 is on my short list.