I have a Nextbase 312 in my sons car - dead easy to put in and set up. Very good value although I haven't looked closely at the video from it yet - not had cause to.
I had a Nextbase 420G in my Freelander for two years, but, the battery packed up although Nextbase replaced FOC longer after the warranty period was up. Sadly, afterwards it played up and would't record.
I replaced it with a 412GW and moved the 420G to the Zed after replacing the memory card. I'm still not sure its working properly, but, I'll be using a goPro with an external battery when needed.
The 412GW claims UHD but it isn't - its half way between HD and UHD. I use mine in HD mode. The higher resolution chews up memory at an alarming rate. I don't think the video quality is as good as the old 420G though. It isn't as sharp.
The memory cards take a real hammering as they're being used all the time you're driving. I've only managed to get 12 months out of a single card, but then thats with 15k miles of driving.
The current models are dead easy to move from one car to another - all you need is an extra mount for the screen and power cable. That plugs into the mount and the carer simply slides into the mount. You can leave the cable plugged in (and tucked away) and the mount on the screen. Even the old model is easy to remove, but, the power plugs directly into the camera so needs unplugging before you remove the camera.