Android is great but its core is more complex. Having all the options to customize (like no other Phone OS) comes with a price : security and stability, plus, battery life. Android makers are now moving to Quad-core CPUs, to get the same performance WP8/IOS delivers with 2 Cores. Battery life is still an issue, and won't change a lot precisely because all of the OS core features (it's strength compare to others), is also it's greatest weakness (consumes more battery power).