In general, I am enjoying this product. It keeps my coffee warm for several hours on battery and longer time on the charger. My only disappointment is the insulation. When I put hot water, I cannot hold it comfortably. And also it doesn’t maintain the heat like any other good quality mugs after the battery runs out. If I pay this much money, I also expect a good insulation. I do hope Ember solves this issue in the future for their new products.