I can't say what's the best for SD, but the NYPD uses the Speer Gold Dots and they've tested lots of ammo before deciding what 35,000 members are issued. They do have certain concerns regarding what to use that may not interest those outside of the PD.
But for me I've been carrying Federal Hydra-Shok JHP for years in .32, 9mm and .40S&W. When I use up my old ammo that I've carried for a couple of years I generally shoot at plastic bottles, cans, cast iron skillets and anything else I can get my hands on. I'm no expert where ammo is concerned, but that ammo sure causes a whole lot of damage to whatever I hit with it. I suppose it's as good as anything else available from off a gun shop's shelf.