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.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips