Having previously used the Spyder 4 Express, I decided to give ColorMunki a try after seeing it advertised in a photography magazine. The software disc that came in the box would not run, so I downloaded the software from the Xrite website - the difference here compared to the Quick Start instructions was that the device had to be connected to the usb port before installation. The device was very easy to configure, with a wizard taking me through each stage of the process. The device measures the ambient light & then it is placed on the monitor in order to calibrate the display. The process took about 10 minutes & a profile was created at the end. In normal use the device can be connected to the PC usb & set at the side of the pc in order to monitor the ambient light & adjust for any changes. It will also calibrate a projector. Compared with the Spyder I would say the ColorMunki Display is better, but it is more expensive.