I personally use ADT which I got through USAA. However, bearing in mind that the average burglary takes between 7-11 minutes, a home security system is in reality a personal comfort factor. Dogs, the nosey neighbor, a sign, motion-sensing security lights (I have five), thorny bushes at the windows, double-bolt locks on all doors, drilled and secured sashes on the windows, etc. are all an attempt to convince the perp to go on down the road and hit someone who is less prepared. Now, all of those preparations are assuming I'm not home.
If I'm at home everything changes: the lights, dogs, and finally the home security system are an alarm that announces the presence of an intruder. There are loaded and available firearms in almost every room. There is also a 'safe room' where we can make a stand; a heavy door in a substantial frame at the end of the hallway, appropriate firearms which include the 12-gauge, a flashlight, my cellphone so that I can reach 911 and direct responding officers to my position and location without good guys getting hurt, and an extra set of car keys if I have to get out fast through a back window. My wife and I have both been in law-enforcement and feel comfortable with our weapons. Practice makes perfect - so practice.
My advice is to make the proper decisions before you are in a stress situation if it all goes down bad. Have the appropriate mind-set to be able to defend you and yours and shoot center-mass, don't mess around trying to shoot warning shots or trying to shoot someone in the toe. Keep your finger off the trigger, identify the target, warn them verbally if possible, and then shoot to DEFEND yourself. After it's over, it has only begun unless you have Castle Law and your name is not George Zimmerman. Remember to CAREFULLY articulate what happened, preferably with the assistance of an attorney present.
Personal safety is both inconvenient and a hassle, but the alternative when not properly prepared is usually a lot worse. Being aware of your surroundings and developing your sixth sense, (if it doesn't feel right it probably isn't), and then getting away from a bad situation by quickly leaving is usually the best course of action. When you are in your home you are in your castle and that is why we have Castle Law. There is no place left to go as a refuge and under the law it is assumed that he that breaches your defences has done so with this knowledge and is prepared to pay the consequences.
Sign me as a retired cop, and a ten-year instructor for the NRA's Refuse to be a Victim Seminar.