Agree with Gorgo, battery wears out quick when on GPS and there is a long list of stuff that is not quite up to par. For instance:
GPS Tracker cannot run in background, so whilst you have your tracker on you are ok, but if your phone rings it will stop transmitting.

Its accuracy is average
Because it has to be on the whole time the GPS transmits all the time wearing down your battery. It would be better if you could set the interval at which it polls the gps location just as you can with the sending of location back to the server.
There may be other better apps out there for tracking location on the iphone, but I haven't found them.
Best thing about this one is its free.