about 7% is a big difference, for me .
I turn off the phone during the night, but I use it a lot during the day.
Web, mail ... GTalk ... 1-2h of music ... and more.
This was bother me at Nexus S (ICS) .. Every day I had to plug it into the charger.
SGN ... Battery takes 2 days, not bad at all.
(off .. but the champion is HTC Radar - my primary phone ... battery .. 3 days without any problem)