"low cpu usage" This is not true on all the platforms. For instance, in my experience I found it that blackberry's and android's versions are quite good. But iO

"low cpu usage" This is not true on all the platforms. For instance, in my experience I found it that blackberry's and android's versions are quite good. But iOS version (on a 3G) and Windows Phone 8 version are very cpu demanding which result in draining the battery pretty quickly. WPH8 is the worse, although it is probably because a limitation of the OS (they had to had the audio sdk in order to make notifications work).