The mug works as expected. It heats up my coffee nicely. However, some things that I don't like in this cup: first the outside is plastic - if it were ceramic, that would be better as it gives a better impression of the mug. I also don't like the fact that the switch/button is at the bottom of the mug, which makes it hard to use. The light/indicator is not very bright either so sometimes it's hard to see.