Needless to say, trial lawyer organizations hate it almost as much as they hate tort reform.

Prior to the SYG laws, even if acquitted at trial based on self-defense, you could, and often were sued civilly. It became a clichéd joke about the burglar or mugger who would sue you for "unsafe working conditions" but sadly it was often the case.

SYG grants immunity from being sued by the person you are defending yourself against. It also stopped all prosecution after a judicial hearing (much cheaper for all parties than litigating a full jury trial). There is another provision (though I am not sure how it operates in practice) that can make the state libel for defending yourself in a criminal action that is deemed Stand Your Ground.

In the Zimmerman case, the defense elected not to persue a Stand Your Ground immunity before trial. However, they have essentially stated that they will do so if the Martin family, or anyone else, files civil suit against them. Zimmerman would most likely win any such SYG hearing based on the fact that he has already been criminally acquitted based upon a self-defense assertion.

I am not sure if attaing SYG status after the criminal trial, when they elected not to have the hearing pre-trial, would triger the states financial obligation for the defense or not. Personally, I don't think it should; but as a matter of law it may. Isaac might have an idea there.