I know this is an old thread, but I just thought I'd share my experience with the 10MP Arecont Vision Megavision compact - the AV10115 D/N to be specific. The heat disappation is very apparent, and this thing needs good ventilation.
The lowlight shots are very disappointing compared to a 3MP Hikvision, but according to what some posted in the 10MP camera thread - the higher MP just makes the light situation worse.
I thought the relatively large sized CCD (1/2.3") would benefit it also in low light, but I was very wrong.