I have been running them about 8 months on a set of 3xAA.The battery connects with a JST or you can use a LiPo.
In my case one GPIO(Interrupt enabled) port is connected to a reed switch attached to a window. This port also has a capacitor to provide a time delay to debounce the window closing. Sometimes it can default to close an older window and you don't want to trigger the sensor multiple times. This was much easier than trying to do this in the firmware.
The firmware is based on the JeeNode Room Sketch. The node stays in sleep mode as much as possible. Wakes up every 5min to send an update of each sensor to the DomotiGA server. A trigger on the reed switch will wake it up instantly and push an update.
I have one node with a thermistor and another with a DHT11.