Don't have a fullsize or ever shot one, but the compact is my edc. The unique lockup is reason enough to own one and if you understand it's benefit of durability and accuracy the more reason. Simplest takedown of any pistol and a very good DA/SA trigger to boot.
I am considering buying a PX4 Compact in 9mm or possibly .40. I would prefer to have a G model ( decocker only, no safety). My other consideration is the FNX.
You can easily convert it to a "G" yourself, or take it to a gunsmith, did mine in about 10-15 minutes. Take apart the de-cocker and remove the detent ball bearing and there you have it, you will need a punch also. Or, order the flush decocker from Beretta and that will make the PX4 a "G" model as well.
One of the nice features is the rotating barrel, which has the same effect as rotating the bullet. The bullet flies straighter down range and the barrel recoils straighter. This reduces barrel flip and makes the recoil easier to handle.
I've had a 9mm PX4 Full Size as one of my pistols for several years now and have put hundreds of rounds through it without any problems. Accurate, reliable, and ergonomic. A real fine pistol. And good looking too. It's one of my "keepers."
I am a new owner of a full size PX4 Beretta Storm .45 caliber model F (positive action safety, decocker DA/SA). It is my first gun. I have about 1200 rounds through it. Most of the ammo has been Atlanta Arms and Ammo reloads, but about forty hollow points as well. It has had about 6 failure to loads during regular firing all with the ten round magazine. (It came with a ten round and a nine round magazine.)
I recently shot at my first IDPA (International Defensive Pistol Association) competition and had no issues with it during six stages and about 75 rounds (again AAA reloads). I bought it for two reasons, first several people (from gun enthusiasts to dealers and gunsmiths) tell me that it shoots great the recoil is more easily managed than the regular type nonrotating barrel guns, and secondly because I wanted the positive action (lever) safety that was not available on many other guns. As a first time owner and soon to be Concealed Weapon carrier I felt like it would be a good feature. At the IDPA competition all safety mechanisms must be engaged when shooting and it does slow down your times a bit. I still feel it's right for me though.
I also shot 50 rounds through a PX4 full size .40 caliber prior to buying mine and it shot without any failures or snags.
I would not feel confident in telling you about accuracy or reliability simply because I do not have the experience necessary to do so. I have read though that some accuracy is given up for extreme reliability and have seen videos of the Storm dragged through a muddy swamp by a string tied to the trigger guard and then loaded and fired as well as a video of the same guy carrying the gun through the swamp underwater for a minute then just simply picking it up above the surface and firing a magazine off.
I hope you get some information out of this that helps. Keep us informed as to your decision.
For what it's worth: I had a Cougar, the Storm's daddy, and it NEVER failed me. It was really easy to work on and given that mine was in .40 I never gave the recoil a second thought. That Brutonion (?) finish has got to be one of the toughest out there. It was my first every day carry that I really stuck with (over a year). Everything about it just always worked. It ate everything I gave it. I liked the fat grips that were designed for *comfort* NOT flat sided to hide under your coat.
The ONLY reason I got rid of it was the DA/SA trigger. I just couldn't get good with it. My everyday carry now is a 1911 commander from S&W. A Series E 1911SC with Scandium frame and rounded grip.
I tote a subcompact. It uses the traditional tilt barrel
system. Plenty accurate. My viridian C5L fits underneath
handsomely. The grip is fat. I prefer the joints of my
proximal phalanges to line up under the trigger to give
me a natural point of aim. They wont. It took a few rounds to learn how
to shoot it.