On 9/25/12 I got the notification to update my Galaxy Nexus to JellyBean Android 4.1.1.
Here is my experiment:
First 12 hrs only the preinstalled apps
Next 12(which included overnight) I added Google Drive and Calorie Counter
3:38p battery completely discharged
Next 12 Facebook and GoSms, hdfullscreen caller id and Draw Something
Battery did seem to deplete faster with the last 4 added...will hold off
Phone kept charge over night waking up to 43%? still
From 8:30a-10:30a that 43% was used up.
Next 4 to be added when battery completely discharged again.
As of yesterday battery lasted about 12 hours (@10:59p it was @ 39% and had been on 10h6m 32s). I went to bed about 1:30a and that's when the phone died. What I did notice is the battery seems to also charge quicker. About 2:40a the phone was fully charged. I unplugged to see if that practice would make a difference throughout the day. The battery had the red exclamation point about 6:30p. Little to moderate use throughout the day, was actually busy at work.
I believe a factory reset probably did help. I will continue to add apps until I see there is an issue that affects the battery life. Best time I saw was 1 day but that too was with little to moderate use and very few apps.
Hope your journey leads you to a happy place...I"m happier but still not wowed! :-)