The new Beretta PX4 Storm full size 9mm got it's initial look-see today. It also came with three backstrap options. I switched them out and decided on the one that came installed. The switching sides of the magazine release went much smoother than the CZ. If anything, with the PX4, it was a pain prying the first backstrap off.
I like the gun. I'd shot a friend's compact in the past. Slide removal/install is the easiest ever. Just pull down on two small levers (one on each side) and push the slide forward. To put it on you put it on. Other than being a little pokey to my sensitive digits it's perfect.
Comparing triggers to the Beretta M9, I have to give it to the M9 overall. The DA feels more or less the same on both. In SA the M9 seems to have less takeup but most of that could be due to the PX4 having more curve on the trigger. Break seems about the same but the M9 brings the hammer down a bit more. Reset goes to the M9. Trigger pulls feels lighter on the PX4.
There's a tiny chirping noise on the PX4 when the hammer is going back. I need to figure that out next.
EDIT: Hoping for magic, I threw some break free in a couple spots (a spring and a moving piece that might be rubbing the slide). Maybe a little. It's only noticeable when you thumb-cock the hammer. Maybe it's caused by sideways pressure from my thumb because there noise isn't there when instead it's the trigger causing the hammer to travel rearward. Strange. <shrug>
I liked the PX4 9mm that I shot. I actually shot better with it than my 92FS.
Have you modded your M9? If not, you can swap the mainspring out with a mainspring from the 92D models. If youre curious, just google "Beretta 92 D spring swap". I did this on my 92F and 96FS Vertec. It lighted the DA pull by about 2lbs and SA pull by about 1lb and I havent seen any issues with light strikes on primers or any malfunctions. Easiest $5 trigger job out there as it only took a few minutes to do.