well it will drain your battery if your using it alot on apps like facetime or downloading larger files over 3g. 3g will drain battery faster than wifi so yeah if this app is being used it will drain your battery faster...think about it. For me, i have it installed and do not use it overly too much, it is always enabled for facetime and the app store but i have never noticed any battery drain on my phone due to this tweak.