Usually my P6's battery last 2 days (switching it off during the night), with 3h or 3h and 30min of screen turned on.
When i don't use the phone, i always switch off mobile data, wifi etc.. for me battery life it's not bad but it's not so good.
It's ok.. i'm happy with it and it's not a problem :good:
(B125 rom, JB 4.2.2)
To shed some light to the situation, I use Samsung Galaxy S3 as well. None of the phones is the primary one since I use them somewhat equally (P6 is useda little bit more than the S3).
Sometimes when I don't use the Galaxy S3 (like when installing ROMs), the battery on the P6 is from 1.5 - 2 days.
I've used a Galaxy S3 last winter, for 3-4 months.
I think that with screen on, battery life on S3 is greater than on P6, especially while browsing internet or playing games. But battery life on standby, with S3 wasn't good as on P6.. and if mobile data or wifi were turned on, it was terrible, like -10/15% per hour
At the end i also think that they are equally about battery life, but if you use a lot your phone, S3 is bit better than P6