Ring and Nest don't tell you about the tier based monthly subscription required to actually obtain your recordings from their servers when you buy the cameras/doorbells. Last I looked (which was a while ago) I believe 3 days of still images was free, 1 week of recording was $10 and 1 month was $30. This is all PER CAMERA and you know that the price is only going to increase over time.

Doesn't take a math magician to figure out an NVR with a fairly large HDD could be paid for fairly quickly depending on the number of cameras.

For people that are worried about fires, we have had a building go up in flames and even though the recorder was bad the hard drive was fine and we could still pull the footage off of it for the fire marshal to determine the cause (this was a mechanics shop).

If you are worried about theft, than put SD cards in the cameras and have an NVR. If they take the NVR you will still have some footage on the camera SD card.