Overall, night time footage is much worse, even though it claims to have night vision mode with infrared LEDs, turnings this one has no effect at all. However, the video is 720p and wide angle and for such a cheap device is actually pretty good quality. The cam loops the video as well, so that means once it's out of space on the 8Gb microSD card I have in it, it start overwriting older files. It also turns on and starts recording automatically with ignition and similarly turns off gracefully when the ignition is off. There is a rechargeable battery inside it to power it for a little while after the engine is off.
So here are some screenshots from the footage of day vs night. I tried to pick similar situations for each.
Highway driving at night:
Highway driving during the day:
Street driving at night:
Street driving during the day:
At night the quality degrades badly when there are lights present like traffic lights, lights from other cars, etc.
Here's a video of the actual footage.