I found something very interesting while testing the past few nights. I set both Hibernate settings as was previously mentioned in this thread. When plugged in over night it never entered hibernate. Last night I kept it unplugged and it did enter hibernate.
One other thing they need to fix here though. We don't need separate settings for Display and Sleep. They both do the same thing on a connected standby supporting machine. And in fact if you set one the other changes with it if you are increasing the duration.
For me I seem to be back to normal behavior and battery life. Moderately used the device all day on battery and then left it over night and I have 45% right now. The trick for me, clean install with the drivers from MS site installed before enabling networking and remove the SD card. When it was in, power management is FUBAR.
So may be a combination of having bad drivers and / or SD card inserted.
Hope springs eternal that in todays updates (They seem to update every Tues and Thurs) that they have an update for connected standby machines that also fixes the SD card battery drains. And would it hurt to fix the default applications section to allow us to set the calendar as the default for appointments. But I digress.