1 hour charging --> 7% battery
Battery flat again in less than 20 minutes
Battery usage graph: see http://imgur.com/9i1M1KO
I have been using it for about a year and this thing is basically falling apart. It looks well built and sturdy but the inside is a whole different story. I was at the service center recently and I overheard that many people are switching to other brand of mobile phones because of these issues. So many problems that affect even the basic functionality of it.
1. HTC One Camera can't capture images of reasonable quality. It has a purplish tint or hue which distorts the colour and makes images basically unusable.
2. Frayed HTC One original charging cable wire, the insulation wears out quickly and individual wires can be seen, some damaged.
3. When charging HTC One via computer, it starts the sync tool. When you close it, after a few seconds it will start again. Also, it keeps asking you what to do with the documents inside again and again, leave it alone and you have 30+ dialogs stacked one on top of the other.
4. Calls starting to break up halfway even in locations where this does not normally occur
5. (!!!) HTC One Battery life drains very very quickly. If the night before it is fully charged, the morning after I wake up to see the battery is at 70%. 6 hours later, the battery is flat. I often get an alert saying that the phone is using up more battery than the charger is able to provide. Even when I close all running programs and processes, even when I activate 'Extreme Power Saving Mode', this only provides marginal improvement of about 2 to 3 hours. It defeats the whole purpose of having a smartphone and it doesn't compare to some other phones which you don't have to charge so often. Basically now it's plugged into the charger most of the time
It was bearable initially but these problems have become worse over time. The last straw was when the phone consumes more power than supplied by the charger even during 'extreme power saving mode'!
When you read smartphone reviews, please bear in mind that the reviewers probably test it for only a few months, and when they do so, often they are not using it as their main phone and so, it is not representative of what you will experience. So please, do not buy HTC One.