Out of the box I can tell it is a superior camera to the Foscam FI9900P. The Foscam always gave me good image quality during the day except in bright sunlight. I haven't got to check that yet with 5231 because it has bee cloudy lately. Night time is where it really excels. I haven't had a chance to play with the all the available Dahua adjustments, but just using the defaults, the night image is much clearer. You can also adjust the IR level which i think will be a plus. I was having some issues with night images on my Foscam front door camera, so I thought I would try a 5231 there. One thing, is there is more barrel distortion on the Dahua, but it is a true optical zoom where the Foscam is digital. Here is a link to some shots off my Foscam cameras. You can see it is doing some weird images at night.
Camera upgrade from Foscam to Dahua suggestions
Here is front door shots at the widest view with the Dahua, you can see the barrel distortion. No adjustment on the settings yet. I used the existing Foscam mount, so it probably not the best angle for this camera. I am thinking about getting the IPC-HDBW4231F-AS Mini Dome for the Front Door and putting this camera on the Driveway.