Board Thread:General Discussion/@comment-5023546-20130910031001/@comment-19448006-20130915121929

The d20 system is not just a more direct system, long and short term regarding campaign length, but also easy to pick-up, and use etc.

The Percentile or Centenial systems, however, give you an indication as how much you succeed or fail a test by. It basically has the critical hit system built in.