I'm currently shooting Federal® Truball™ Rifled Slugs out of my 870. I am happy with the accuratecy. I tend to stick with what works. The only trouble one never learns anything new like that. :biglaugh:
My uncle told me many years ago to use the brenneke rifled slugs in the smooth bore barrels because they were the most accurate at the time. I believe i purchased them from sportsmans guide a while back.
I also tried the remington rifled shotgun sabots in my smooth bore too and found them to be accurate too. (50yds) I have an old model 12 winchester pump with a smooth bore slug barrel.
My smoothbore 20" 870 is my home defense gun. I find I get fine results from cheapo Remington Sluggers rifled slugs(approx 15rds for $9). Good enough for me anyway as they are one of my go-to home defense rounds. I can make a cloverleaf at 50yds with iron sights. Works fine for deer back in the woods and I wouldn't hesitate to try one out to 80-100yds. The sights and my eyes start to get out of whack long before the gun gives up.
This setup is pretty dang handy as far as an all-around home/self/truck defense gun. Iron sights and a mag extension giving me 7+1 of 2&3/4" buck/slugs is quite formidable I'd like to think.