Good for straight-on shots to the chest.
Little penetration if you hit an arm first, or the angle of incidence puts the bullet on a path where the vital organs are deeper than the penetration of the dispersed pellets.
Also, I've come across at least one report of a defense pelvic shot where an x-ray showed the pellets dispersed up against the pelvis. But they didn't break the pelvis; thus the bad guy didn't go down from that shot like he might have if a .40 or .45 had broken it.
I recommend studying up on the desired characteristics for defensive handgun ammo. You'll quickly come across explanations for each characteristic. Once you understand the importances yourself, you'll be able to evaluatefor yourself.