Got to play with it today at work. I purchased the 12 tooth brake with a full choke. The pattern at 25 yards using Federal Premium 9 pellet 00 was (as expected) a little tighter than with the stock choke. I also noticed a slight amount of recoil reduction too. Bonus!
Oddly enough it made my shot pattern with Wolf 9 pellet 00 WORSE at 25 yards!!! Use quality ammo if this is going to be a serious defense gun folks!!!
Didn't try it out with slugs...