I bought Blink back when they did their kickstarter, before Amazon bought them. I have 5 or 6 of their cameras in a box on my shelf. The app was always rubbish, couldn't view more than 1 camera at a time, and if you wanted decent motion detection, etc, they went through batteries quick.
The delay was pretty bad, tried to use one at my door to see/hear people come up. By the time I got the notification, loaded the app, loaded the video, the people were gone.
Ring seems to have done things a lot better, at least with their door bell setup, but again, the delay can be troublesome if you want to "answer" it, but just viewing/recording, it seems to do better.
Ring has a $59 camera that uses 110v that looks interesting.
I also have security cameras up, running off of a linux server for NVR, and they are wired and use PoE (Power over Ethernet) and of course, the data goes over the ethernet. This is a good system I've setup, using Dahua cameras that are fairly inexpensive and good quality. Problem is, my system is all local, if they cut my power and take my server, I have nothing to show the police.
I don't have the bandwidth to shove that data into the cloud, without encoding it heavily, and then, the video isn't that usable. I may try out one of those ring cameras as a backup to my wired system.
Also, as to the "cloud", it's a marketing term for servers that are not local to you. Most of the time they are clustered geographically, so if one goes down in a location, everything still runs in another. IT people have been doing this for decades in different data centers, but cloud is just a new term for it.
Technically, I run a private cloud with my servers. I have one at home, and one 100 miles away at a colo. They keep data synced between the two. It's not cheap, but it works well for my uses.
