UPDATE: I'm on day three owning this product. I have handwashed, never microwaved, and used only plastic implements to stir my drinks, avoiding touching the bottom with even those. Today I placed the empty mug on my counter and stepped away to brew some coffee. From across the room, two minutes later, I heard a faint cracking sound and came over to look. There's a roughly 1cm circle of delamination at the bottom of the cup after two whole days of use. I may try again if they come out with a more durable second gen model because I love the idea, but for now I'm going back to my regular, non-smart mugs. Extremely disappointed in a product that I was really excited about. Luckily Amazon has an easy return policy...........First of all I want to say that I really like this product, despite its flaws. It keeps my coffee at a temp I like, and that's all I wanted it for. That said, it's got quite a few issues.A larger capacity, longer battery life, and water-resistant charging coaster would make it a better product overall, but all of these things are disclosed in the product information so I can't really complain too much there. The edges of the handle are somewhat sharp so you have to hold it just right or it digs into your fingers. Totally workable, just maybe not as comfortable as it could be. And although it's minor, I would like it if the custom color light was actually useful in some way. When in use, the mug defaults to solid or flashing white to indicate temp readiness; it looks fine, but why include the option of a custom color for identification purposes if it only shows when the mug is empty? Why not just use the custom color to replace white altogether?More importantly are temperature inaccuracies. If I have mine set to 135, my coffee cools down to around 120, as read by three separate thermometers, and keeps it there. Or, if I set it to 145 and pour in a cup of room temp coffee to heat up, the app will read 145 when it's actually around 120 and continuing to heat. Over an hour later, it's at 130 (so it is still heating up, despite the app saying it's holding). The temp is fairly consistent between the top and bottom of the cup, which is nice, but it's often the *wrong* temp, and by a lot.And then there's the finicky app. It's clean and intuitive, but simply doesn't work well. In addition to the inaccurate temperature reporting mentioned above, there are significant connectivity problems. I'm guessing the latter causes the former. Occasionally the app just decides to say that the cup is empty when it's full, or vice versa. The brightness setting resets itself over and over throughout the day. Often it won't connect to the mug at all. Sometimes this resolves by itself, and sometimes it doesn't work until the app is reinstalled and the mug set back up (luckily a fairly quick process, but not one I want to have to do several times a day, especially after paying 8-16x what a regular mug costs for something that's supposed to be smart).The cup itself, while not perfect, generally does what I need it to do and keeps my coffee at a tasty temperature, but it sure would be nice if it played more nicely with its own app and didn't fudge the temp quite so much.