Hexus posted a review on the Cooler Master MasterCase H500M
A quote from the article:
Cooler Master has released a third version of its H500 case, this time called the MasterCase H500M, where the M implies it is a high end ‘Maker’.Cooler Master MasterCase H500M Review
The original H500P suffered in various respects, including problems breathing through the front panel. These issues were pretty much fixed with the H500P Mesh, and now we have the H500M with glass on four sides along with ARGB (Addressable RGB) lighting in the two 200mm fans in the front. It is worth noting the H500M is an additional model to the range and does not replace the existing models.
If you stand back a short distance the H500M looks fairly similar to the H500P Mesh, however a closer look reveals a list of changes that add extra bling and pizzazz. The most obvious differences are the extra glass panels and the revisions to the power supply cover. You will not, of course, appreciate the new ARGB lighting in the two 200mm fans at the front until the PC is built and ready to run, however that is a treat that is worth waiting for.