Right, so I decided to see just how long my battery would last with my normal use. I charged it fully, then used it as I normally would and let the battery drain to within an inch of its life.
I have to say, its pretty impressive compared to my Nexus 4, and I think it would have lasted even longer if I was not working on a site with very little or no signal. However, one thing that has interested me is that the email app has drained more battery due to low signal than the actual phone has by "searching" for signal!
Admittedly I am not a heavy user of the phone, but I have been streaming live video on Safari a fair bit, using facebook, email, texts, a couple of calls etc etc. When I went to bed last night my battery was at 11% (11PM). When I got up at 06:20, it was at 7%. I set a backup alarm because I didn't think it would live through the night, but it did