I had the dash cams & external battery installed by Car Toys at the recommendation of my dealership (I drive a 2020 Subaru Forester). The guys at CT did great work, all the wires are neatly tucked away and the camera's placement doesn't interfere with my Forester's Eyesight system.
The adhesive that comes with the cameras is excellent for mounting to glass, but my rear camera is mounted to a textured interior panel and the adhesive didn't hold to it for very long. It fell off after less than day. I slapped on some double sided mounting tape about 2 weeks ago and haven't had any trouble since.
So far the camera works great and does everything as advertised. I am noticing that it somewhat regularly locks files on its own so I'm having to reformat the card every other week when it runs low on "unlocked" files that it can overwrite.
The app is pretty sweet overall. It makes changing the cameras' settings a breeze and I can check their orientations very easily with it. I did have some issues with the app not letting me download video files to my camera, which magically fixed itself after I restarted the camera. The new problem now is the app will give me an error when I try to turn off the camera's recording in order to change the settings. It's not a big deal though, I can still manually end the recording at the camera itself and then the app lets me into the settings menu.
Overall I'm totally happy with this purchase!