For home defense, I use regular Foster type slugs in my Remington 870 20 gauge.
At the close range of home defense, I really don't feel the need to buy premium slugs. The longest shot I'd ever take would be from the front door to the curb, about 50 feet.
I can put the cheaper Foster slugs (Remington or Winchester make) well within a 9-inch paper plate at that range -- enough to stop an engine, reach an occupant or flatten a tire.
Frankly, I don't see much point in spending up to $5 per round, when the $1 a round stuff will work just as well for the same purposes.
Now, if I were hunting, I'd want the most accurate slugs I could find, for precise bullet placement to bring down game humanely out to 75 or 100 yards.
If I'm shooting at an aggressor at 100 yards with a shotgun slug, I'm almost certainly outside the legal definition of self defense, or it's time for me to reach for my Ruger Mini-14.
I have a log cabin on a lake in the Chilcotin region of British Columbia, Canada. Up there, for bear medicine, I load my Browning A5 with Foster type slugs.
At the close range I would have to shoot a black bear or grizzly, precision accuracy is not required.
Most of the locals have 12 or 16-gauge pump shotguns in their cabin, loaded with 00 buck for the first shot and followed by Foster slugs.
I know of two black bears shot by cabin owners; no grizzlies. In one instance, the black bear was put down with two shots from a .303 British; the other was downed with a 12 gauge slug, presumably a Foster.
Self defense with a shotgun is almost always very close range. Why spend a lot of money on premium accuracy slugs when the less expensive slugs work just as well at the same range?
