I have two of these running separately for the front and back of my 2012 Prius v. Haven't been running them long, but I've viewed footage from both and they seem very clear. I'm using them with CPL filters.
The settings require some initial tinkering, but it's mostly intuitive.
If I had to pick a least favorite aspect, it's that they don't set time/date/timezone automatically despite the GPS module. Additionally, the time zone selections are just presented as "GMT +/- #" which would be much clearer and easier with additional info in the labels such as "CST", "EST", "PST", etc. The lack of auto setting also means that if I need to coordinate the front and back footage for any reason, they will read slightly different times since it's almost impossible to synchronize them by yourself. I'm sure I've done them well enough that at most they're minutes apart, but ideally they'd be the same down to the second.
Still, the GPS labels in the video, speed, etc. seem accurate and make me feel confident that I will be okay in the event I need to provide footage.
They reassure me they're working when I turn the car on by playing their brief, inoffensive startup sound; and when I turn the car off the "REC" light goes from solid to blinking to indicate they've entered parking mode. The hardwire kits also ensure they won't drain the 12v battery too much if I don't use the car for a while.
The use of mini USB connectors seems odd in the 2020s, and the only real reason I can see why they were chosen is that they're relatively thin to be able to fit through the hatch grommet, which was easily the worst part of running the cables. I do think there should be some other solution to both make pulling them through narrow grommets easier, and also to use more common, modern cable types.
But, since the mini USB in my case is only providing power and not data throughput, I guess it's not too important. The main issue is that extensions for mini USB are scarce (I'm pretty sure mini USB is all but gone from the consumer space for anything other than dashcams, and for good reason) and I need to use one for my rear camera since the "extended" hardwire kit is still insufficient for my needs.
Viofo says they don't recommend using extensions but I literally have no option since I needed 1440p 60fps front and back.
My nitpicks aren't quite enough to subtract any stars, though. They work well enough so far despite my gripes and I'm fairly impressed for the price point.