Yeah, the 500 does feel kind of junky, but I wouldn't depend on another pump really. It has redundant extractors and that loose fit helps a lot with reliability. They are very dependable. Also, if you've ever seen Mossberg's demo shooter, I can't recall his name but he's on "Impossible Shots" a lot, you'd think twice about calling 'em junk. He can do more with a Walmart off the shelf Mossberg 500 than any of us can with the best custom Benelli. Promise you that.
I also don't need killer accuracy in a defense shotgun. But I do need one that ALWAYS works. A Mossberg does that if you take care of it, and a Mossberg can take a LOT of abuse. Army issued 'em too, mostly for breaching tools in Iraq, but it had to do the same thing basically --go bang when it had to in a sandy environment.
A Mossberg has a good fit actually, that is why it works so well. What it doesn't have is tight tolerances, and if you want those AND reliability, it is gonna cost 'ya. With a close range defensive pump shotgun though, you just don't need close tolerances. In fact, I'd wager looser ones are better for reliability (to a point) in a pump shotgun.
Benelli has its place though. I'm considering one, but only because of 3gun. I understand it is hard to be competetive without one --and I already have a great rifle and pistol for it, so I kind of need it. I hear anyway. For HD, I'd use neither the 500 or the Benelli, I use an M4 --I have a bum shoulder sometimes.
Finally, as for finish, I agree. Their Mariner finish held up pretty well against falling out of a vehicle at 70mph, beat and scratched to heck, but it held up and worked fine. But their blue has always left something to be desired from me, and their park finish scratches so easy it is really good for nothing else than tooth for a Duracoat application. Which I did btw, and it is holding up superbly well. It doesn't get used much, but the old G17 that got the same job at the same time does, and it is holding up just as well. Good prep, good stuff so far.
I wouldn't give up my 500 for anything. That along with a few others are considered minimum required arms for me. Everyone should have one --because you can depend on 'em.
But if you want a little better one, get the 590 military model that has the all metal safety and trigger guard. I just don't use mine enough to justify it unless I can find those parts at a show.
Just gotta keep the muck out of the barrel. Both are easy to run a patch through and I've learned to carry a cleaning rod in my shell pouch for such problems afield. I'm USUALLY graceful enough to land with the gun butt down if I am holding it, don't have it slung. Once, i tossed it and fell flat on my face. It was REAL wet that year and I had problems with the salt grass and cow tracks as well as my waders getting stuck and coming off. 
and my 590 did my "venting" for me.
