This is a quick walkthrough of the vendor evaluation criteria and a couple of uses for that information. How you come up with your criteria or evaluation methodology would be up to your procurement teams. Depending on the type of criteria there are a number of reports and other data that could be used from Dynamics AX to help you determine the rating. The vendor evaluation criteria just provides a place for you to store that data. It can then be used in searching or displaying on the employee services portal when employees are searching for products.
Cheers
Lachlan