I am an attorney and these self-defense insurance programs are mostly scams. I know a guy who is one of the attorneys that a major company sends its clients to. The clients are all very lucky that they've never made a claim, as this attorney has never done a murder case before; he's never tried anything over a misdemeanor.
You're probably never going to shoot someone. It's extremely, extremely, extremely rare. And if you do, most states will not send you to a grand jury if everything looks to be in order (i.e. you greased an intruder in your home, there were witnesses who saw the dead guy try to knife you in an alley, etc.). If all of the above fails, you're really going to want to choose your own counsel. Most attorneys don't accept prepaid legal services, and/or aren't on the list of "approved counsel" for these self-defense insurers. In my experience, most of these self-defense insurers are actually set up by attorneys as a revenue stream - lots of people pay in, nobody ever makes a claim.
Also, most are not truly "insurance." They don't pay all your bills, just a flat rate. I saw someone above post that their program pays up to $10k in the event of a self-defense shooting. That's chump change. When I did criminal work, I charged $10k for our state's equivalent of a felony three / class "C" violent felony. Ten grand will probably get you about a week of full-time work from a competent and reputable attorney, taking a murder or manslaughter case through to trial will be closer to $50k, plus another $6-10k for expert witnesses and additional costs. Add more if there's an appeal, and add another $25-30k if you have to face a civil suit. The point is: if you have to shoot someone, and if it's a clear case of self-defense, you're most likely going to incur well more in legal fees than any of these self-defense insurers is prepared to pay on your behalf. Put the lawyer on a credit card, let the bankruptcy judge sort it out on the other side.
If you really feel the urge to spend money on this sort of thing, go find a lawyer you like, and who is capable and experienced, and put the guy on a retainer. At least that way you can call him up with questions, or use your retainer for other legal services as they become necessary.