What testing has happened and what is the battery life?
There are now over 450 users of Tracker and no reported issues with regards excessive battery life. Expect around 6% battery use per hour if live tracking, and half this if just using text messages.
Some examples are given below, I would recommend you perform your own tests for your own handset and battery. In all cases Bluetooth and WiFi both switched off (recommended)
Outside of the application, consider setting your phone up for power saving:
and after you have started tracking I recommend ...