If not a subscription, at least accounts for everything (have you heard of that coffee mug that requires an account and firmware updates?)

The battery life (on mine at least) was bad. The saucer part (which is the charger) broke on me twice. The pogo pins that connect to the contact ring on the bottom of the mug broke. It was often a crapshoot whether the mug would connect with the app on my phone.Which was a pain in the ass to have to use the app all the time to make changes to the temp (or see what temp you were at) and I actually discovered the I like the way the flavor and of coffee (and especially tea) change gradually as they cool (this isn't a fault of the mug of course) and having the liquid always be hot robs you of that gradual flavor change (especially with tea). I also found the coffee to have a strong cooked flavor if you had to walk away and stop drinking it for a while. I also found it annoying to have to hand wash the mug every day (instead of throwing it in the dishwasher and grabbing a new one). And at the end of the day, since it was a corded object. You always had, at the very least, a saucer with a cable coming out of it running across your desk whether you were wanting to use the mug or not.

TL;DR; it's a fun novelty, but so much more hassle than just using a normal coffee cup. Also, had some quality issues with mine.