Recoil is at the 40cal level. It is a slightly shorter but snappier recoil pulse than the 40S&W but overall very similar other than duration.

If you're able to try a Glock 22 in .40, you'll get an idea of what a Glock 31 is like to shoot. All opinion here, but most people like 357 Sig for ballistics rather than competition as it is a lot more expensive than a box of 9mm ammo, it's closer to 45 ACP in price. It is a nice round though. I have a Sig P239 in 357 Sig, one of my favorites.

I find it less recoil that the .40 but heavier that the 9mm to me its closest to my .38 super

.45 Hard recoil, .40 Medium, 9mm Softer I'd say it's between the 9 and 40.