My HTC One handset is due to get the Android 4.4 Kit Kat upgrade before the end of January. Personally, I didn't see much of a difference between Ice Cream Sandwich and Jellybean so I was hoping somebody with a Google Nexus device or anyone using a custom ROM would be able to shed some light on what to expect once Kit Kat appears on my phone? My main concerns are to do with battery life. Each version of Android seems to take a little bit more out of the battery than the previous version. Is this the same with Kit Kat. Also, do you find that the "OK Google" functionality works? Again, what effect does this have on the battery?