Glad to hear you are considering the BI route! You can totally leave your comment here, it’s all constructive and this info might help someone in the future.
Motion
Okay so a few thing I should point out about motion detection. Blue Iris supports two motion detection modes. It can always use video based motion detection, which is alright but does cause quite a few false positives. It can be fine tuned quite a lot but you will still have issues like birds, bugs, sudden light changes (sun coming out from clouds) causing false motion alarms. Also, if you have a lot of cameras and a weaker computer, video motion detection can be quite taxing on the CPU.
The other mode it supports is on much higher end cameras that have built in PIR motion sensors. These are the same sensors alarm systems use and they are extremely reliable. The problem is that these cameras can be extremely expensive and only really make sense in an industrial setting. Because of this, I am getting ready to use ESPHome to set up motion sensors around my home. These will then trigger a motion event in Blue Iris AND update a sensor in Home Assistant.
Further integration
There are quite a few guides specifically about integrating events between BI and HA, because Blue Iris has a built in MQTT client. All you do is set up a mosquitto server on hassio using an addon, and then create a mosquitto user and add it to Blue Iris in the IO and DIO tab of settings
My setup
I have 5 [SV3C 1080P Bullet cams](SV3C POE Camera, 1080P IP Camera Outdoor, Home Security Surveillance Camera, Wired, 20Meter Night Vision, IP66 Waterproof, Onvif, Stabler Connection Compared with WiFi Cameras(Series L) https://www.amazon.com/dp/B01G1U4MVA/ref=cm_sw_r_cp_api_i_1byjDb3XS3P2N) and they are really solid. They are also some of the cheapest bullet cams on Amazon with good reviews. Blue Iris supports just about any camera imaginable, but these are the only ones I have experience with. These have pretty great IR night vision, and I think they are low profile enough that they look good, but it’s also not hard to spot so hopefully thieves see them and go for the neighbors instead lol. All of them are wired to a PoE switch in my attic which is wired to Ethernet downstairs. They were a breeze to install since they just screw into anything, and they only needed one low voltage cable (no electricians!) to a PoE switch.
Like I said earlier, these are cheap cameras and they don’t have PIR motion detection or many other standalone features. If you go for higher end models like those with PTZ, Blue Iris will most likely support anything they have.