Other than android device manager, what apps works great when your phone is lost/stolen. I came across Cerberus how it works?
Cerberus is good.
Suppose someone finds your phone and tries to unlock it, if they enter the PIN/Pattern/Password wrong more than 3 times, it uses the front camera to take a picture of them and it emails it to you.
However, it has a trial period, and after that you will have to pay for it.
IMO, Android Device Manager is great provided you have mobile data permanently enabled.