As mentioned a few times, the GS3 has the best battery life of the many phones I have tested with medium to good signal. The bad thing is it easily has the worst battery life with a weak signal.
It gets so bad in weak areas it would be nice if there were an app that would dynamically turn off the data radio at a certain signal strength threshold.
It is a great device, but has gosh awful power draw in weak signal areas. As example, the Incredible, DX2, Droid 3 and Razr also drained more with weak signal, but the GS3 is in it's league of bad compared to them.