After ordering, trying, and returning several I settled on this make/model for our vehicles: AUKEY Dual Dash Cam*

It uses capacitors instead of batteries so supposedly this makes it better in southern cars where the internal summer temperatures can get over 120F. I hardwired each directly to an "always on" slot in the fuse box of each car so that it records even when parked. The only issue with that is it does slowly steal power from the car battery if it's left sitting for a long time. The video quality is good, it's easy to program, and it came with cables more than long enough to run the length of a Toyota 4Runner and a Honda Pilot. I've had them for several years and they are still going fine.

The others I tried either had too short of cables, glitchy rear-facing cameras, or flimsy construction.
-Blast