Easily one of the best purchases I've ever made.
I bought one of these about five or six years ago, installed it in less than half an hour, and then basically forgot about it. Rarely, if ever, checked if it was still running or if there were any problems with the memory, nothing. Then, recently, while I was sitting at a red light, the person in front of me suddenly threw their car into reverse and floored the accelerator, slamming into me and causing over $4000 worth of damage to my car alone which took 3 weeks (of renting a car, another $1000) to fix. Within minutes of the accident, I had the dash cam video downloaded to my phone, showing in crisp detail how the other person was at fault. The field of view is very wide and license plate numbers show up clearly on the videos. Your current speed also displays on the downloaded video so you can prove you were stopped or going the proper speed. Audio quality is also really good, which is embarrassing for me as someone who likes to sing in the car haha, but can be extremely useful.
The only negative is that while my car was in the shop, the suction cup for the front cam melted. I lived in Texas for years without it melting, so I don't know what they could have done to make that happen! I asked VAVA about a replacement (customer service was prompt and polite) but apparently they don't make spare mounts, which is baffling when it's a known issue. But I just made a little wire cage that hangs from my rearview mirror that the camera now sits in and it's fine. (Actually it's better because the suction cup did tend to occasionally fall off the window.)
Planning to purchase another for my hubby's car. This one saved our bacon!