I got one of these way back as well. The design is not good. It performs it's main function well, but everything else it does it does stupidly. For instance, t

I got one of these way back as well. The design is not good. It performs it's main function well, but everything else it does it does stupidly. For instance, the lid didn't have enough threading, and as a result would spill coffee. I don't know if they've fixed that, but it was clear just from looking at it that it needed more threads. Travel mugs are just far more unpleasant to drink out of, and when coffee is about 140 degrees, I don't find myself spending hours sipping at it. It takes me about 5-10 minutes to go through. A heavy mug already perform this task alright without the clever phase transition, but I drink enough coffee for it to be worth $100 to slightly improve the situation with a mug with the wax tech in it.