Starting with a very basic VGA camera and progressing to better quality 720P and 1080P cameras, this video compares Catan's 5 Dash Cam models, more info at www.catan.ca. This video doesn't lie, don't get fooled by dash cams which claim 720P, many are VGA, and if that quality meets your needs then that is great, but if you want better quality ensure the company you're dealing with is upstanding in their claims of quality and camera specifications.
Actual footage of video from cameras is actually clearer due to compression used for Youtube posting.