iphones are usually known for their better battery life than Android, even compared to Android devices with larger batteries. There is also standby time, the battery drain when the phone is not used. I could comfortably say that iPhones are superior, until I experienced Marshmallow vs iOS 9. I have a 6S and a 5, both on iOS 9 (9.2.1 as of my subjective observations). When they are on standby, they seem to be sipping battery a lot more than they're supposed to. My iPhone 5 can barely last two or three days (connected to wifi) before the battery is completely drained. Its battery was replaced by Apple last year as part of the replacement program, so it's not due to old battery. I can also observe my 6S not lasting much longer, maybe additional day or two. This is without Facebook app installed. In contrast, my iPad mini 2 has no problem lasting for days (obviously due to larger battery). I also have Andoroid phones. Prior to Marshmallow, their standby battery life were not any better, as expected. But after I put marshmallow, they can last for at least 4 or 5 days easily with plenty of charge left (unused, connected to wifi). I have tested on OnePlus One and Xiaomi Redmi 1S, and they both still keeping significant amount of charge after 4 or 5 days. I can see them even lasting for 7 days. This is quite a feat imo. I believe on usage time, my iPhone's would still be superior. However, Marsmallow forces me to think. Why can't my iPhones do as well, or better? Or is my observation an anomaly? I didn't play with any power settings (I didn't put any devices mentioned here on their respective low power mode). Interested in hearing other people's experiences.