I received the Ember travel mug as a Christmas gift. This is something I never would have bought myself. The battery life isn't the longest lasting, but I spend most of my day at a desk so it is usually on the charger. It last long enough to get through one cup of coffee though, maybe an hour or so. 
What really made the mug worth it for me was the excellent customer service. After a few months of use I broke the lid. After a scouring the internet for a replacement, I couldn't find one for sale, I emailed customer service. They answered promptly and we able to get a new one shipped out to me quickly. I love my mug and appreciate the excellent customer service.