I'll throw in my experience with the Stoeger M2000 field model. I bought a M2000 before they came out with the defense version, but the action is the same I believe.
The action is an inertia system, the same that Benelli uses, and Stoeger uses it under license because they are owned by Beretta/Benelli. It's very simple and easy to take down and clean, if it ever really needs cleaning. A drawback is that it kicks a bit because it needs recoil to operate the action, but I haven't really noticed much difference between the Stoeger M2000 and the Remington 870. I have read that in semi-auto shotguns gas operated systems kick less due to using some of the gas to operate the action. I can't speak to that, though.
To be completely honest, I can't think of a single instance where my Stoeger failed to cycle. I have had a few instances of shortstroking my 870, though. User error, I know, but still the Stoger has had no problem with light Federal bulk-pack target loads, buckshot, or slugs. It just runs.
I knew a guy, older and more experienced than I, that was apparently convinced to buy his own Stoeger shortly after I bought mine, and he apparently hated it. To each their own, I guess. I've run into other people at the gun counter who were looking for a shotgun to backup their Benellis or Berettas or whatever, and they were looking at the Stoegers.
I think Stoeger had some problems early on, as most do with new products, but perhaps that's all smoothed out now.
Hopefully this has been somewhat helpful to you.
