This paper describes the designs of the TDWR and ITWS Microburst Detection algorithms, and compares their performances in the Orlando, FL and Memphis, TN environments. This is the first study in which the performance of the TDWR and ITWS microburst detection algorithms are compared using an identical data set and a common set of truth criteria. Examples are presented illustrating common scenarios which create the performance differences. Detail is presented on the impact of the ITWS VIL (Vertically Integrated Liquid water) test in reducing algorithm false alarms. This algorithm feature is currently being considered as a retrofit to the TDWR algorithm.