For pure self defense in urban situations with heavy restrictions nothing beats the versatility of a pump action shotgun. Even in a Ferguson-style riot situation you're unlikely to have to defend your home at a range greater than 50-60 yards, which should be just fine for a slug. And it's pretty hard to miss a perpetrator at 10 yards with buckshot.
I don't own a shotgun but I would if I lived in an urban area.
The only thing i disagree with in this statement is that its hard to miss at 10yds. The patter from any of my shotguns with buck shot at 10 yds was measured in inches, and at that less that 10.
Under stress, and operating on the premise that a shotguns scatter will be fairly wide at that range (this comes back to practicing with your chosen weapon enough to be completely familiar with it and its loading) making a solid body hit becomes questionable.
Where i see the shotgun having a major advantage in these situations is the increased wounding potential. slugs or good buckshot will put serious lead on target if properly aligned.
Good defensive ammo reduces the amount of recoil youll need to cope with and will help you get back on target faster, but again without practice I feel the shotgun losses the advantage to a short semi auto rifle (why my wifes getting the highpoint).