there is no round on earth when used in a practical application better at stopping a human being in it's tracks than 12 gauge 00 (double-ought) buck shot
it is, however, kind of a beast to shoot if you're not used to it. home defense shotguns are relatively cheap and are among the most reliable weapons ever made. its hard to go against one when talking about strictly home defense use.
I'd also like to know why some of you have so many guns, what's the purpose of that? Should I really own more than one?
everything has a different application for which it's best suited. your concealed carry pistol is most likely not the best for target practice, your hunting rifle isn't the best for home defense, and you can't carry a shotgun around town unless you're in some third world scum pit
its a lot like having more than one tool in your tool box because a spanner wrench won't fix everything