I had a 320 Compact in 357 Sig, which is sort of the analog to a Glock 32 but really more in between the size of a 31 and 32 (or 22 and 23, etc).
I didn't shoot it enough to wear out or damage anything, but put a fair number of hot loads through it and do have a couple thoughts:
- Compared to both a Glock 31 and a 32 (full size and compact 357 Sig) my 320 was definitely snappier with the same full power ammo. I've put a lot of rounds through big bore magnum revolvers so I'm not talking about the 320 just "kicking too much" one shot at a time, but looking at it from the perspective of multiple shots in a string my 320 definitely gave up some time and control to the Glocks. I don't think this is the same with 9mm versions of each where recoil is mild enough to not matter much. My caveat here is that I've put a lot more rounds through Glocks than the 320, so it's what I'm more used to.
- The .40 and .357 are undersprung in these guns; Sig uses the same recoil springs for 9, 40, and 357. I had to make my own heavier spring, brass ejection was 20-30 feet and slide impact with the frame was a noticeable hit during recoil. Still, I never noticed any physical damage to the slide or frame components.
- This part may not matter to you, and may have been just my sample, but ballistics from my 320 were a full 100 fps slower with most of my loads than the Glock 32, even though it felt snappier. While that may not matter much on target, it seemed like a lose/lose situation in that area.
- A personal quibble: like most Sigs, this one shot low for me. I really don't like the way Sig sets their sights for a "combat hold" where the aim point is the center of the dot rather than the top of the sight like everybody else. That's not specific to the 320 though, and varies between users and different guns so YMMV.
Other than those things, I really liked the feel of the gun, and it was pretty accurate. Mine had a GreyGuns trigger in it which felt pretty good, and takedown was pretty straightforward and easy. The 320 grip modules (both full size and compact) feel great in my hand so I understand why some guys really like them.
Just one guys experience and opinions, but hope that helps.