Also battery life is largely pointless for an app developer to lose sleep over. The tiny power saving you make will always be eclipsed by screen brightness, cost of poor networks (the radio won't sleep) and apps like Facebook which happily sit in the background with their VOIP mode active.

Not to mention users will punish you far more if your UI is poor or features are missing rather than if it chews up battery (which they largely will never be able to measure). I don't know many ordinary users who check their battery usage deep down within the many Settings submenus.