If you don't 1) already have a shotgun, and 2) know how to use it well... there's no particular reason to choose a shotgun for HD, IF you have something else that you can handle/shoot better and have more confidence with. Heresy, you say? Well, charge on, scattergun brethren, with your charge of heresy. But hear me out, and think about this a bit.
My sig line says- mindset, skillset, toolset. What comes LAST in the equation?
Hardware.
THE SHOOTER is the most important element in the equation. The shooter's mindset, and the shooter's skillset, are FAR more important than the mere tool chosen for the job. How often have you heard said here- "Most any gun will do, if YOU will do?"
A better question IMHO to ask is this one: "Is a shotgun enough of a better choice for HD to make it worth while to buy one, and learn to use it effectively?" And the answer to that one is IMHO a resounding YES! It is a better defensive weapon for several reasons.
1) Long guns are easier to hit with under pressure than handguns. Four points of contact with the long gun (shoulder, cheek, shooting hand, support hand) make it more manageable than two points of contact with the handgun (shooting hand, support hand).
2) Long guns in useful defensive calibers are sufficiently more powerful than most handguns to give them an overwhelming advantage for defensive purposes.
3) The argument of superior maneuverability with a handgun is completely offset by proper training in the defensive use of a long gun. Likewise the retainability of a properly employed long gun in trained hands is at least equal to that of a handgun. And no one who has any options is going to be out searching their house alone if there really are indications an intrusion has taken place.
THE ONLY reasons for moving out of a secure location in that event are to secure children or other family members who are sleeping in other rooms, and a well planned floor plan and a good home defense plan will minimize even that. See the class information for Personal Protection In The Home at
http://www.nrainstructors.org/CourseCatalog.aspx . Look into taking that class, or at least seeing the DVD of the classroom portion of it at
http://materials.nrahq.org/go/product.aspx?productid=ES 26840 . Louis Awerbuck's video
Safe At Home is also very good IMHO-
http://www.paladin-press.com/product/129/73 . But hands-on training with a good instructor is the best possible approach IMHO.
I personally believe a good reliable shotgun in trained hands is the best possible weapon for home defense, or personal defense at close range. With its larger bore size and heavier projectile weight, it is a devastating antipersonnel weapon. It does have disadvantages- everything does, after all. Shotguns can be heavy, recoil unpleasantly, have limited magazine capacity. All those can be overcome with careful, open minded selection of the best gun for the individual shooter, with good fitting of gun to shooter and with good training.
Of course, YMMV.
lpl