I've used the PhoneLocator (the free version) for a while, and I am delighted with the Pro version too. The SIM functions which alerts you abt. the SIM change,and the thief calls is neat ! Find out who is calling, if you forgot your phone at home is very useful too (in my case at least)! Track your phone position if it moves from the last position, is something that I don't seen on other similar apps. The interface of the application is well designed, with nice icons that represents the function, which also make the set-up easy and intuitive. My opinion is that for this price, the developer is offering a lot - plus the app works flawless !