We purchased our 8-camera system from TS2.
http://ts2net.com/prodmobile.html
I am reluctant to provide advice about camera types because technology changes so fast and I have not kept up. It might be best to contact these folks and Safety Vision with your color-camera and night-vision questions.
The cameras we chose were color, not infrared (night vision). They do best in daylight. At night, they will record images that are lit. The better the lighting, the better the image. They do not see in the dark. We chose color over black and white because the price difference was not significant. If you can get color video at little extra cost, why not?
While we have a nice monitor in the dash, we do not drive down the road with it turned on. I know people use theirs when driving. To me, it is a distraction. I'd rather use the windows and mirrors. When backing up, the rear camera us used all the time. It provide great comfort to see the area immediately behind the truck as you back up. At night, the vision behind the truck is as good as your lighting. Having a backup camera does not substitute for getting out and looking before you back up or having your codriver serve as a ground guide.
Note that our TS2 system was more expensive than Safety Vision offered when we shopped. That is because our system is a survellaince system. A digital video recorder captures images from all eight cameras 24 hours a day, whether the truck is running or not, whether it is occupied or not. The images are kept on the recorder for up to five days before it loops over itself.
We view the system more as a liability management system than a driver's aid. While it helps us back up the truck and keep an eye on the freight inside, we bought it more to protect ourselves from the unsafe drivers and loading dock people out there who might cause an accident and then try to blame us for their faults.