My typical experience with people running windows as a server for Moodle is because they like all things Microsoft. Wincache is developed and supported by Microsoft and appears to work well as a MUC store. The only "problem" is that the Moodle plugin hasn't been developed (yet) to allow wincache to be used to store the session (memcache has). It wouldn't be hard to modify the existing code to add support for wincache to store the sessions. Used in conjunction with PHP 5.5 and the built in opcode with the latest Moodle code I've seen Moodle perform a lot better than some other configurations I've seen.
Wincache can be used instead of memcache (although I haven't done any qualitative comparisons of wincache vs memcache on a windows server.)