Here is where I'm coming from...
I live in a 1000sq.ft, 3-bedroom condo. Exterior walls are brick and cinder block. Interior walls are sheet rock with metal studs.
The entrance is perpendicular to my stepdaughter's room. The master bedroom (where me and my shotgun are) is located on the opposite side of the condo from those two things. If a BG gets into the house and I confront him BEFORE he gets into the Master Bedroom, my stepdaughters room's wall is the backstop.
Any shell with pellets larger than #1 birdshot is going to be a pretty big risk for penetrating the wall and door of her bedroom. But at distances of less than 20 feet, I think that even 2 3/4" #7 birdshot is going to "stop the threat", and if the first shot doesn't do it, there are 5 more in the tube...
IF we lived in an all-brick house, I would be thinking differently. If the bedrooms were configured differently, I would be thinking differently. If it were a multi-story house I would use different ammo. If our home had big rooms and LOTS of open space, I would think differently.
But in this dwelling, with this configuration, my FIRST concern is my family's safety. Second concern is neighbor's an people outside. And my LAST concern is what other people THINK makes the "best" home-defense 12ga shotgun ammo, before they know the details of my specific situation.
Every home is different. Every scenario is different. Choose your ammo based on the layout and construction of your house, NOT on the opinions of a bunch of armchair tacti-cool net ninjas who may have never actually fired a shotgun inside an enclosed space.
Let some of these yuck-a-pucks go out to Chantilly VA and run through H&K's "tactical shotgun house" training a few times, and THEN they can tell us about how much fun it is to fire off several rounds of 3" 12ga in an enclosed space without hearing protection, because I can tell you from experience that it is NOT fun. Neither are 2 3/4" shells, but at least with them, you get your hearing back within a few hours, as opposed to a few days...