My Nexus 5 sat at 80% battery remaining after 26 hours off the charger this morning. This with regular checking of emails, a couple of Facebook forays, some quick tests of a web app, and all of the services and background apps such entails. And despite my office/business being in a rural area with very sketchy cell coverage (thus the phone has to work much harder).
Of course if I used much more screen on time my duration would be single digit hours instead. But such is the problem with comparing battery times when we all do different things with our devices, and use them in significantly different conditions.
That's interesting, for my nexus 5 (granted it's only a few days old so perhaps there is some break-in) seems to go down to 80-85% in 10-15 minutes of morning web surfing/reading.
With high brightness and a lot of active, screen-on use, it will absolutely chew through the battery (though 20% in 15 minutes is extremely excessive: For wifi browsing Anandtech found it to be among the top devices, actually beating the benchmark iPhone devices. They then removed that result from the listing pending the full review release). What impressed me most from it is the standby time which is extremely impressive, even in difficult conditions.
Of course if I used much more screen on time my duration would be single digit hours instead. But such is the problem with comparing battery times when we all do different things with our devices, and use them in significantly different conditions.