Has anyone used Metz 15 MS-1 Wireless Digital Macro ring flash? If so could you please tell me how it compares to Canon MR-14EX TTL Macro Ring Lite Flash?

Sorry, I haven't used the Metz ring flash. I can tell you that any ring flash, even one that allows for ratio control, is going to produce light that looks almost flat compared to a standard camera flash on a bracket or the MT-24EX. IMHO ring flashes are great -for portrait and dental photography...