I have been doing a little test with my Nexus 5 now that it has Android 5.0. One of the projects that was included in 5.0 is Project Volta which is supposed to increase battery life of Android phones.
Battery life on Android phones is notoriously bad, particularly when it comes to idling. This has basically to do with the multitasking nature of the Operating System.
Well, today I have had my Nexus 5 for 12 hours without doing anything and it just used 9% battery. This is a real feat if you ask me. I guess it is not iOS level yet, but it is a noticeable improvement. If I can do a more scientific test, I’ll do so and share the results.