quik trak has been around for quite a few years now.
there are limitations with some systems in that they'll use the GSM network (mobile) to track the car. But that means they can lose the cars signal, just like you would sometimes lose a mobile signal.
Then there are the GPS systems, which again, have some limitations.
So the best, if there are any, haven't really looked into is, is to get one that possibly offers both types of coverage.
Fairly price, i think about $1000-$1500 install and first year monitoring, and then you have to pay each year for monitoring. Great peace of mind though. The control centre can do things like remotely lock the car, kill the engine, etc...