Not so much data so far, as I use GEAR for only one day - however after "regular" workday I still have 70% of juice ...
I use the watch for notifications and to dial last numbers mainly, as I talk using MW600 - it all runs smooth and headset takes over the voice even if phone call is started by the watch.
Apple Newton 120/Handspring with phone module/Ipaq with phone backpack/MDAII/MDAIII/MDA Pro/ATHENA (Ameo)
HTC HD2 / Galaxy Note / Galaxy Note 2 / Galaxy NOTE 3, Samsung GEAR Watch, MW600, MW1
Currently using: SM-N9005 + BT Headset Sony MW600 + GEAR Watch