I use Winchester AA light trap loads for the house gun, 7 1/2-8 shot. At across-the-living-room ranges, its wicked bout excessive penetration is not a problem. (I live in an apartment building)
Ron said he wasn't worried about wall penetration.
Seems to me, either load would be devastating at close range though.
Ultimately, that's all that matters.
One other thought to consider...though how many home invaders have it...body armor. If there's no penetration which one gives more "oomph" on impact.
Several telephone books taped about the body make cheap yet effective body armor. Tape some around a log or to a plank of wood when you go scatter gun testing to see the difference.
Tape the book to a board (as if it were taped around the body or made into a taped up vest) and then shoot it with shot.
Of course a slug will go through it and skeet shooting is stupid.