The charging coaster itself, like the mug, is a generally good product. It works as intended. Its unfortunate that I need a second coaster but the mug's battery life doesn't cut it when you spend several hours having your several cups of coffee. So one for the kitchen and one for the office. In any case, the major failing on the Ember product is not the hardware but the app. Its quirky and inconsistent behavior take what would otherwise be a very good product overall and makes it just okay.