IMHO the CX4 is a bit of an acquired taste.
There is a lot that I love about it, especially the weight, size, and magazine flexibility (and depending on what you own, potential magazine commonality with your pistol). The ergonomics are okay, and I personally think the design is visually very sexy.
But there are also two big things that I did not immediately like or enjoy; the cheek-slap from the big bolt, and the long/creepy trigger.
The cheek slap surprised me, as I was not used to big blowback action firearms and was expecting recoil like the M1 carbine. At first, I really did not like it at all, but eventually I have grown to not hate it (I still don't like it, but I can tolerate it now).
The trigger, too, was surprising. Loooooooong take-up leading to a heavy pull and a spongy break. Even as a guy who likes milsurps (which have a reputation for not exactly having crisp triggers), I was surprised at just how terrible the overall trigger experience in the CX4 was. I really think -- still think -- Beretta's engineers should be embarrassed for how that turned out (regardless of their motivations for why they designed the fire control system the way they did). I own many different types and brands of firearms from across the spectrum of quality and purpose, and I consider the CX4 trigger the worst of all of them by far.