Battery does not last very long and this mug does not hold temperature very well beyond the set temp.  Also, for me, the highest setting of 145 degrees is lukewarm.  My ember now sits on a back shelf taking up space.  Combine the thermal properties of a Yeti type mug with a significantly higher max temperature eg 185 degrees and a superior battery and (with the new travel charger) you would have a grand slam.  A somewhat larger capacity would be nice too.