I was not saying it was an issue or bad product. I work with electronics daily so I understand issues occur with them. It would drop the wifi signal is what I ended up determining with mine. it was the only device on the network that would constantly drop out. I have a full TP Link OPmada set up with a total of 6 Access points covering my total property which is 1/4 acre. I can walk down the street a good ways and maintain good wifi signal. The network is not the issue. I was thinking it had something to do with heat build up because the front door gets direct constant sun for the entire afternoon. I initially thought it was power related but after testing the transformers, all of them were fine I say transformers because I fired the parts cannon with out testing initially. The Nest has been on line since I set it up and has never lost connection. I like the control over the DB1 versus the nest but I love the lack of wife bitching with the nest.I'll say that I haven't had any issues out of my EZVIZ DB1 or DB1C cameras. The DB1 is probably over two years old and the DB1C is probably a year old now. Both have been in continuous operation since I purchased each of them and I've had zero problems with them. I have a decent power supply and multiple wireless APs around the house to ensure good wifi coverage. Those two things can play a huge role in how reliable these camera are. I also only use them to feed my BI machine via their RSTP feeds. I have never tried to use the OEM app/software for anything other than setting up the cameras. I know the cameras will loose sync with the OEM software after just a few hours usually. I've always assumed it's because the cameras cannot access the internet and therefore cannot "call home" to the EZViz servers.
For a wireless camera that uses your existing doorbell wiring, I think the DB1C is as good an option as anything else available today. But I would certainly recommend the DB1C over the DB1 because the image quality is much better on the DB1C.
If you can use POE at the front door, then that opens more possibilities and the DB1C may not be the best choice.