This mug is great. I haven't tested with any equipment to check on the accuracy of the temperature, but I keep it on the 3rd to highest setting and I have steaming coffee from start to finish. I mostly have my coffee in my office, so I'm able to use the charging coaster almost all of the time and I never worry about battery life, but I have used it on the weekends when I'm not in the office and it's lasted for a couple hours at least. I didn't keep track of the time, but it was long enough for my morning routine, so I didn't worry about it. It was at least a couple of hours. Just throw it on the coaster when I'm done on Saturday and it's ready for Sunday to do it again.I wasn't sure how much I'd love the gold version, but my wife asked me to get something other than black just to be a nice pop of color on my desk. I did, and I do like it and am glad I opted for the gold one, although black would have been great too.