The gps tracking device is a controversial piece of technology. Some people see it as an extremely useful device and others see it as a huge invasion of privacy. Both parties are correct and ultimately it is up to you to decide if you want the device or not.
One of the biggest advantages of using this device is real time gps vehicle tracking. Vehicle owners now have one more weapon in combatting vehicle thefts by using this device. The device can pinpoint (to within a few feet) the location of the vehicle. This makes, chasing and tracking down the stolen car a very easy thing to do. Even if the car has been shipped overseas, the owner and law enforcement can still track it, as long as the device is intact.
For companies that rent out vehicles or deal with a large amount of vehicles, this is a vital device to install in the vehicles. With gps tracking fleet management becomes a piece of cake. Not only can stolen vehicles be tracked, but errant Taxi drivers, Truck drivers etc. can all be tracked and brought to order. None of them can blame delays on traffic and their indiscreet stops, illegal fares etc. can all be monitored.
Although the flipside of the coin still exists, no one can argue against the usefulness of the device. As with most electronic devices, a price must be paid to enjoy the convenience. The possibility of an invasion of privacy must be weighed against the usefulness, before the device is purchased.