We did a videotape a few years ago for a competing system then called, On-Guard.
On Guard is GPS based so your car can be tracked anywhere. Lojack has a very short range and frankly, most Police Departmenets don;t want to be bothered with it. And..many departments don;t have the equipment anyway.
My Father has On Guard in his Lexus. There are panic buttons mounted in the car. When pressed...the response center will listen to what is going on in the car. If they don;t like what they hear, they will direct the Police to your car. I also understand that an option is available that allows them to shut the car off. My Dad wouldn;t be without it. They will also direct you if lost, etc.
One more point. If you were to buy the On Guard just for theft prevention, it would be worth it. When you start your car, you have to press a button to turn it off. If you don;t they will be notified and contact you in the car. At this point, you had better be the right person and know the password.
I'd look into that and avoid Lojack.