So I've now purchased 3 of the battery-mounted Nest/Google Doorbells. Two of them broke. And I've read about a lot of other people having this issue. There is a clear defect with the mounting mechanism of these devices. After a certain period of time, the mounting spring (or whatever it is) stops working, and the device simply falls off the wall. I've contacted Google and they simply said it's past the year warranty and will not support it.
My recommendation would be to stay clear unless you only want it to work for a year.
