I've recently re-activated my Vehicle Tracker System, as it was a prerequisite from my
Insurance company. My experience has been very positive from Vodafone. (Note - VF acquired Cobra in Jun 2014). In order for the fob / service to work, you have to be a subscriber (approx £207 pa).
If you are a subscriber, you must
NOT keep the fob in the car! This defeats the purpose of the VTS if the car is stolen. You have to keep the fob on you, in a pocket or a wallet, which is a bit annoying but doable. Don't keep it on your keyring either, because if your keys are stolen....you get the picture.
I moved my car literally "around the block" last week and forgot the fob. Within seconds I got a text, followed by a phone call less than two minutes later. I was actually quite impressed with the efficiency.
@Gollom - Removing the fob from the car will not disable or hinder the car in anyway. The fob merely transmits a signal to the Operations Centre. Only if you are a subscriber - should the car move without the fob being nearby, you will receive a Text Message followed by a phone call. If you are not a subscriber, nothing will happen if the fob is at home and you are out driving.
The VTS Centre staff can see the exact GPS co-ordinates of the car, and the speed it is travelling at. If you confirm the car has been stolen, at that point, VTS can immobilise the engine remotely when deemed safe and also alert the Police. They only do this on your instruction.
A separate discussion can be had around whether or not you'd want the car back. I must admit, I personally wouldn't but I don't think you get the choice. Having said that, now that I have the VTS activated, I quite like it! I just hope I never need to use their service, like any form of
Insurance.