I have been using this mug for a little over a month now.  The fact that I still use (when there are SOOO many other mug options out there) speaks to how good I think it is.  But here are some areas where it loses that 5th star:fi
1. The three hour battery life is based upon something other than the highest temps.  I prefer my coffee hotter than average and so battery life for me is shortened.
2. The top used for drinking fits by friction only.  It does not take much at all to remove it.  Be warned!
3. Other Ember mugs have digital indicators on the side that provide useful info.  Not this one.  One LED only.
4. They should offer a bundle option of buying the mug with multiple charging bases (work and home).

Other than these shortcomings, you will not find anything that can do what this mug does at 16 oz (finally - 16 oz!).