Fully dishwasher safe and cheap enough to buy several so you always have a clean mug and lid handy.
I don't store liquids for hours, so the fact that it is not a Thermos-style mug is fine. Keeps liquids hot for an hour or so. Best for taking it in the car and drinking there. The lid's drinking hole is open, so it's not something you'd throw in a bag and expect to not leak. The simplicity and ease of cleaning make it ideal for my purposes.