I wanted a POE ip doorbell cam with relay outputs. I did NOT want wifi or batteries. Yes, the doorbird is expensive, especially the oil rubbed bronze flush mount that I ordered.
It arrived fast and was easy to set-up and install. It was recognized by my Hik Vision NVR, but after a reboot it takes 10-15 minutes to show up again on the NVR for some reason, even though it is online with the door bird app. You cannot set the doorbird for static IP, but you can bind the IP and MAC address in the router. This is important because if the IP address changes the NVR will think it is a new device and need you to re-enter the password. I have had no problems with the NVR recording and playing back the doorbird feed along with many other cameras.
I opted for the cloud recording at $4 a month (a bit high?) but it says unlimited recording for 7 days. The cloud is great for door bell presses because you can play back a short clip instead of the single pic it sends you. I also have the motion activated cloud recording turned on. I'm waiting for them to complain because every car and person triggers the motion sensor. It's recording clips every minute or so during the day. I've found that playing back a clip from the doorbird is easier than using the NVR, but since the cloud is limited to 7 days I do have long term backup on the NVR.
I'm 3,000 miles from the unit and it takes a second or three for the notification to come through on an iphone/ipad.
I also wired relays from a second legacy door bell and a gate access controller to the doorbird pushbutton (a little soldering) so I get instant notification of anything on the property. This is much easier than using alarm inputs on the NVR, especially for other family members who have the doorbird app on their phone.
The only complaint, other than the price, is that at night the IR LEDs turn off and the camera switches to color mode, so you get a grainy color image until the motion is detected or the button is pressed, then you get a good b/w image. You can manually turn the IR on for 1 minute. Not that big a deal as I have other IR cameras, but seems a little odd that it doesn't default to B/w at night even if the IR LEDs are off.
I'm not a reseller or rep or associated with doorbird in any way. I'm an RF engineer who owns a design firm and likes to have remote viewing and automation of my houses, so don't waste my time by accusing me of being biased.