Product review (5 stars): Accurate temperatures, easy to use, good value
I bought the base unit and have two extra remote sensors (for a total of 3 outdoor sensors).  I have just finished setting it up, so I don't know about battery use by the base unit.  I do like that the remote sensors have rechargeable batteries, so they won't be using up batteries.  The 3 remote sensors agree within 0.2 degrees Fahrenheit.  The base unit agrees with reference indoor thermometers within 0.5 degrees Fahrenheit.  However, be patient, allow 20-30 minutes for the readings to stabilize.  The sensors have good range - 50 feet in my case.  During synchronization mode all sensors were read repeatedly.  Once synchronization mode is done, the base only continues to read the last sensor that was read; you can toggle through the sensors with the channel/sync button on the back.  I'll update this after I've used these for about  6 months.  If there hasn't been an update, everything is fine.