Usually these things sell for 20 bucks but with this you are getting 2 for half the price. It keeps my tea warm, and the table mug is just amazing. I wanted something that I could use it while driving and the tall mug solves the purpose. I am not an expert on these things, but I know that it is exactly what I wanted.

I bought the copco coffee mug set recently and I must say that I'm a bit disappointed with the construction aspect. So far I have used the travel mug it's pretty aesthetically pleasing for its price, but the construction is not at all what I had expected. Although it maintains the temperature of the liquid (assuming prime it with hot/ cold water for 5 minutes prior to the addition of your beverage of choice), it's neither spill proof or stable. The slide tab that is on the screw cap only serves to keep foreign objects from entering your mug and doesn't really prevent leakage if tip over or agitated slightly. If anything it only allows for less liquid would discharge than if it was completely open. Basically if it tips over or you walk with it, you'll probably get wet or scalded in the first case and/ or a pool will start to form in the second case. The word spill-PROOF is definitely misleading and shoudln't even be included. In addition, the skid-proof foam ring is a good idea, however the construction of the handle makes the mug a bit unstable. It gets knockled over quite easily.

Summary:
PRO: inexpensive, good grips, nice appearance, lefty-right friendly, insulating

CON: poor cap mechanism that doesn't contain liquid, travel is proned to tipping over