Well, the instructions are for a previous model, or firmware perhaps.
Reading those, and then the reviews apparently referring to those instructions, I was skeptical.

So, this all got hooked up on my desk first, not my car. This is a real review.

Things I found:

Instruction sheet (and several reviews) says you can only record two streams is incorrect. When you plug in the back camera, all three streams record, every time. There isn't even a way to turn one off, other than unplugging the external camera.

Video quality: great on the forward camera. Pretty good on the interior camera. Not great on the external rear facing camera.
It's OK for video evidence of that guy hitting your back bumper, while the front cam shows a red light, though.

Options: Motion trigger. This works, for a while, then it doesn't. It records several clips then the option just turns itself off. And the recording stops too. So don't use that. It's a bad idea anyway, at a quiet intersection, nothing moving in front of you, motion detect sees no motion, so no video, and a guy sideswipes you. You'd miss that accident with motion detect because it only watches the front camera.
I tried this with and without the "G-Sensor”, as it appears to be a vibration sensor.

Parking: I kind of made that work, by turning Parking + G-Sensor + motion, and it recorded a locked clip when I tapped it with my hand. I had a couple successful clips.
I didn't pursue this very far, because the instructions say to never leave Parking (or motion!) turned on for driving, you have to set both manually EVERY time you park on two different config screens. I thought this mode would just be automatic when you parked. This doesn't interest me at all. I tried it anyway, and ran into the same problem as before. The Motion detect just goes away after a while, and the recording stops completely.

Phone App: For bandwidth reasons, to watch the video on your phone, this operates on WiFi, not bluetooth. Which means connecting your phone to a local hotspot the camera creates, every time. Then you have no internet, because it's a hotspot without internet, right? It's very annoying. I'd rather just have the files and utilities available on the app, download the videos to play them, and use BLUETOOTH instead. That's not how this works though.
The camera continues working while streaming to your cell phone. But the camera is stuck on the "WIFI" screen, you can't exit or use any functions or buttons while connected to your phone.

The APP Viidure, works OK, and there are a few camera settings in there. Not all, just a few. Plus you can download your video clips into your phone.
(HINT: Its much faster to just put the card in your computer with a card reader)

Through 2 days of testing, I didn't experience any lockups while in WiFi mode, or during testing the camera.

For what you get, it will do the job. You don't need to connect your phone all that often, or use motion, or parking modes. Then you have a 3 camera 1080/720/720 system for $89 at the time of this review. That's OK, there's some value there, especially an uber driver situation when you need a camera on the back seat. I’d like a 3.5 star rating for this one.

It's not hard to notice for $20 to $40 more there are 4k/2.5k systems with much higher res cameras, that may have better functionality. I don’t have one to compare, but just saying it's worth thinking about.