This is such a great mug. I have been using it every day for almost two years now. IT HAS NEVER LEAKED! The lid seals tightly and the button for drinking works perfectly. It is great to have something that not only keeps drinks very hot for a long time but also that I can drink straight from. Whether it is being thrown into a hunting pack, or sitting at a table in a business meeting, this bottle is right at home. It is also very durable. To this day mine does not have any major dings. The rubber at the bottom protects it very well. The documentation that accompanied the mug said to be sure to wash out the lid after every use. I of course never do this, and have not had any problems. The mug is still going strong and I will definitely purchase the exact same thing if this one ever wears out.