The bad: -
This camera works o.k. at its native (VGA) resolution; all other resolutions are upscaled and not native giving poor results. The cigarette lighter connector did not work reliably in my 2007 Zafira... changing the language from Chinese (default) to English was not intuitive, the camera snap mode is not worth a light.
Camera does not switch off when power removed (one to two hours on internal battery) but this is what I wanted so no problem, but may not suit you.
Audio is susceptible to EMI (interference) and the supplied manual is not detailed enough.
The camera has only a general setting for auto brightness so on sunny days the road appears in a bit of a shadow due to the fisheye lens.
The good: -
The price.
If hardwired via a 12 volt to 5 volt (DC) smoothed supply with EMI suppression then a 50% improvement in sound and about 10% in vision.
Whilst not up to "HD" standards the picture quality is better than other cameras that cost twice as much and contains more details due to its "fish-eye" lens but this means it has to be positioned correctly to avoid bright sky's darkening the road ahead. I recommend fitting it about six inches (or further) away from the top of the windscreen.
The unknown: -
It's not clear what the 50 Hz and 60 Hz setting does (some have suggested PAL/NTSC) but this is an analogue display standard, not a recording standard for AVI files. Tried both and can't define the difference (daylight).
An analysis of the frame rate (at 640 x 480 or VGA) provided 28 frames per second with a data rate of 10465kbps, with the audio (mono) at 64kbps and a sample rate of 8khz.
A 15 min recording setting generated a file of 81,581 KB on a 32 gig class ten SD card (about 9 hours recording time).
After each 15 min recording session (or 5 or 10) you lose 3 seconds as the device closes the file to the card and opens another (file) for writing. If during the writing of any of theses files the power is removed (for whatever reason, in my case an EMI spike that locked the device) the entire file is lost.
A video/audio out would have been nice as you could then use it as a reversing camera with the addition of a 7" TFT. I note that a HDMI connector (was) installed but not connected (hidden by sticker and now removed).
Summary: -
For the price and once you've realised its limitations this is actually a very good camera for recording accidents/journeys and so on, just don't expect HD picture quality.
The picture quality and sound (recorded a bit too loud) are good enough for this and better than most other cameras under £100.
A good buy.