Start with both. An NVR and BI. Then in 6 months, report your findings.
When you think 1 is a pain in the ass try the other.
I started with a Costco DVR from Nightowl, a very cheap piece of garbage with a shitty Smartphone App that connected, maybe, sometimes, or not at all.
I frustration, I connected all the cams to a Dahua knockoff (
amcrest) 8 channel DVR and ran the Amcrest View Pro App with great reliability on my iPhone.
But reviewing recording on the phone was labor some and clunky and the number of alerts would drive a sane man to the Looney bin.
I was already happy with
Blue Iris @ work and finally got it working alsongside the DVR at home.
But I knew i wanted IP cameras for their tunability, not Analog DVR cameras that only had a few settings.
fast forward a couple years and I'm running 10-11 IP cams at home, with a 16 channel Amcrest and a Nice Blue Iris PC with 10 Terabytes of storage, and a BI Mobile App that is working great for remote viewing from Work.
For whatever reason, BI as a Service, on my PC, will reboot after a power failure per BIOS settings, BUT 3 times now, mine waits for an Admin log in to resume recording.
The Nvr starts back recording on its own in about a minute after a power failure. So if anything noteworthy occurs, I have a redundant recording of about 4-5 days to fall back on on the NVR hard drive.
( I did not see this behavior on the older Dell 7020 I ran on windows 7 or 8.1 without Trusted Platform Module (TPM) 2.0 chips.)