It is an inertia gun. Not only are inertia guns reliable, they have no bulky rings or pistons or any other gas system parts up front, just the magazine tube. As a result they have very slender forearms, making them sit low in your front hand and point naturally.
It reduces recoil somewhat.** I definitely notice the Benelli kicks less than a double gun on those rare occasions I shoot heavy, high velocity (1500 fps) pheasant loads.