See my comment here:
https://news.ycombinator.com/item?id=15296354I'd be interested if you know any shortcomings of these, so far my experiences have been quite positive, though I have only been running a Hikvision and a cheap rebranded one for about a month.
Biggest catch is probably software - you basically need a Windows box or VM for one-time configuration as ActiveX or proprietary tooling is common, once that's done you're all set and don't need to touch that tooling again, just monitor your camera via the standardized ONVIF and RTSP stream.
There's potential security catch too - I managed to dump the firmware off one and crack a telnet password, but I had to manually enable telnet and so long as you do not expose it to the internet, there's not much harm there. I've read about older cameras that had hardcoded default telnet passwords with telnet on by default and unable to be turned off, fortunately I haven't seen anything that egregious yet.
Overall, the shortcomings, while present are very manageable as far as I've seen. Definitely not a perfect "out of the box" experience like a Nest device will be, but cheaper, more flexible and more interesting to me as a tinkerer.