From what I've seen. The Blink is the ONLY wireless "security" camera. The nest is basically an internet enabled webcam.

For example, if your nest goes offline for any reason (including just being off the net or off power) or if one of the phones logged into the nest account goes offline, you loose all security alerts. That's right, if a family member turns off their phone (or even just looses cell phone coverage), Nest just assumes they are always home and never arms notifications on the nest!!

The blink, if it goes offline, it alerts you immediately that it has been taken offline. That and the fact they are cheap and wireless means they can be installed in more places.

Big fan of blink after using nest for years (and sick of it failing, nothing but false positives and false negative alerts).

Nest is cool if you want... a babysitter cam. Where you want to review all the footage of an area where authorized people are active. Blink is good if you need something like a security system where you want alerts when unauthorized people enter an area of concern.

I have had nest cams for 3 years now and have never had the issues you experienced. I don't loose security alerts when my wife turns her phone off. I do get them when she is home and she forgets to turn her WiFi back on, which is kind of annoying. But it does not assume a person is home when there phone goes out of signal. You must have had some setting messed up. I also get notified when my cameras go offline, i get an email and a text. I had to turn them on in the settings. I am interested in these blink camera though. I do have issues with the app saying I lost connection when I am not on wifi and trying to review footage. I think it is because to damn many people have nest cams and their network is bogged down.