Have been using the phone for almost 6 months and I can easily say this is one of the best phones around.
I was using Nexus earlier and though it does not match Nexus scale, Asus has all the ingredients to make it one of the best.
Excellent sound reception.
Camera, speed, ease-of-use, space - all get a 4.5/5.
13 mega pixel camera does the job well in low light conditions n also supports slo-mo video, secondary camera is 5 mega pixel and capable of recording full HD videos.
Call audio was low in the initial versions and the same seems to have been fixed in the latest update.
5000 mAh battery is good enough to last one and half days.