So $3 off Amazon’s price isn’t exactly a huge steal, but I have this mug and it’s fantastic. It’s REALLY good at keeping coffee hot/warm throughout the entire day… I can fill it in the morning, and in the afternoon, it’s still at least warm.
One of the reviews mentions being hard to clean and finding mold… the key is, there’s a latch on the underside of the lid (which is machine-washable, though the body isn’t) that you flip back to open it up to get in to wash it out. Make sure to do that and let it air dry (unless you’re filling it right back up, of course) and you’ll be good to go. Awesome mug, though.