Colour cameras have moved on a lot recently, but basically the difference is with low light. Colour cameras cannot render colour information well because the incoming light has to be split into the three primary colours, so only black and white gives good results in low light.
Generally there are two things to consider. Firstly, resolution. Standard normal definition tv transmits at 600 horizontal lines. VHS only manages to record 400 lines so look for cameras that will operate at these levels. Many cheap cameras only show 260 lines.
Light levels are also important. A reasonable camera will work at 1lux, but for real low level or where IR illumination will be used, look for a camera that will work at 0.1lux. 1lux works in a artificially lit room, and 0.1 lux will work in torchlight.
These days the world is faced with many potential hazards be it in your home or work place, everyone wants to prevent them. So if you are going to buy a CCTV camera, you should consider many things. Some of them are the system, lenses and signal of CCTV camera and more.