Left the SP3 intentionally off the charger last night to see the battery drain. Was 64% last night and 61% this morning (7 hours later). More than I would like but acceptable. Left all the apps running when I closed the type cover (Chrome, IE, Excel, Outlook 2013, OneNote). So a fully charged SP3 would last about a month off the charger. Can't complain about that.
All SP3 power settings are bone stock (never touched them). I did notice that none of the email accounts were used while in sleep. My usual 100 or so overnight system/server status emails came in after I started using the SP3 this morning. Perfectly acceptable behavior for me.
That's fantastic! I had lost 19% so 3% is more than acceptable. Please post back as to if that seems to be the norm for you.