Earlier in the thread someone said short barrels are pointless for most people and I would have to disagree, I'm not saying a longer barreled gun won't work but the short barrel definitely makes the weapon more handy in close quarters. Used mossberg/remingtons are cheap and easily found at any shop. I would be grabbing my mossberg 590 before I grab the 835 or browning auto 5 and I have lived in some extremely small apartments. I also think it's silly to say a light isn't important and I would have to argue a good light might be as important as the weapon itself. You have to make sure you identify your target before you pull that trigger! My 835 is set up for coyote hunting and I can shoot out to 70 feet so I wouldn't worry about range on a SD shotgun. I love shotguns and would go with a mossberg or remington combo. I prefer mossbergs over remingtons due to the location of the slide release.
Also, if your shotgun I's going to be used primarily for self defense I wouldn't put a sling on it and I prefer to put extra shells in a pocket. I'm not a fan of heat shields so I took mine off although it has prevented me from getting dents/scratchs on the barrel. My 590 has a bead sight and I would like to upgrade to a ghost ring sight.