When HTC and Windows teamed up to release a version of the M8 running Windows Phone OS, a lot of people were surprised. Of course, the device worked pretty well despite the limitations of Windows Phone OS (at the time). Something that surprised a lot of reviewers revolved around battery life. The HTC One M8 running Windows achieved multiple hours of improved battery life compared to its Android counterpart. Then again, we all know that Android is somewhat inefficient when it comes to resource management and power usage.