It's definitely not a battery hog. It uses a little battery for sure but nothing significant. The benefits definitely outweigh that small loss for me personally but at least it's optional for people that want to maximise battery. I've had Always on Display on around 15 different phones now over 5 or 6 years and it's a 'must have' feature for me and the main reason I couldn't go back to an iPhone anytime soon. I've never suffered any Ill effects from it either and as the information constantly moves around the screen to prevent burn in. I'm not doubting what you said btw r511, maybe you had a bug in yours that stopped the always on display information moving around the screen?