I have an older Reolink DVR system and it's pretty much plug and play on POE.
Can be accessed on your home computer or via the app. You can save videos on both the comp and app. Cameras also have an SD card slot if you want to use it.
Live streams well and you can set alerts etc.
I don't play with any of the features so it works well for me. View, record, and download.
Its been running 24/7 for almost 5 years with 10 cameras. No issues yet.
We also have Vivint and its been ok. Originally got it because my wife was home alone in a new area with our newborn. It was for her peace of mind.
We also get a discount on the home insurance and in the end only really pay $15 a month with the wash.