Varifocal beats a fixed lens almost every time - the ability to zoom in and dial it in to be able to get the face is what you need.
Too many people get fascinated with the wide angle views that Arlos and such can provide. But the picture is really no different than taking one from the same place as a cell phone - take that picture and then zoom in and it is a pixelated mess.
You would be shocked how close someone needs to be to a 2.8 or 3.6mm lens in order to ID them. The varifocal allows you to zoom in to "pinch points" and get a much closer shot. The trade off is the field of view or what you can see isn't as much, but you then get a clear picture of the person.
My neighbor was bragging to me how he only needed 4 arlos to see his entire property. His car was sitting in the driveway practically touching the garage door and his video quality was useless to ID the perp not even 10 feet away.
When we had a thief come thru here and get into a lot of cars, the police couldn't use one video or photo from anyone's system that had fixed 2.8mm cams - the arlo sure looks nice and gives a great wide angle view, but you cannot recognize anyone at 30 feet out. At night you cannot even ID someone from 15 feet. Meanwhile, the perp didn't come to my house but walked past on the sidewalk at 80 feet from my house and my varifocal zoomed in to a point at the sidewalk was the money shot for the police.
In fact my system was the only one that gave them useful information. Not even my other neighbors $1,300 4MP Lorex system from Costco provided useful info - the cams just didn't cut it at night. His system wasn't even a year old and after that event has started replacing with cameras purchased from
@EMPIRETECANDY on this site based on my recommendation and seeing my results.
My first few systems were the box units that were all 2.8mm lens and while the picture looked great in daytime, to identify someone you didn't know it impossible unless they are within 10 feet of the camera, and even then it is tough. You are getting the benefit coming to this site of hearing thoughts from people that have been there/done that.
We all hate to be that guy with a system and something happens and the event demonstrates how poor our system was and then we start the update process. My neighbor with his expensive arlos and monthly fees is that guy right now and is still fuming his system failed him.
An NVR is going to be running 24/7 as well. An NVR is basically a computer that all it can do is that and usually not very well. I have had NVRs in the past and am now a BI user and will never go back. I didn't see my electric bill go up when I made the switch. I actually still have an old one going just for kicks. We had a power outage recently and the BI computer lasted the entire outage on backup power and the NVR did not - two separate backup units but the exact same model purchased at same time. You run the computer without the monitor on and BI runs as a service and you don't run anything else on it and the power isn't really as much as you think.