An OS is an OS, I only see it when I'm working on it specifically for a client, otherwise it's something that is behind the real point of the PC, the Work or Leisure you are actually using it for.
Over the years since the days of NT3 Microsoft's operating systems have progressively improved where it matters, "under the hood". the User Interface is largely irrelevant, it just needs to allow you to access files and open programs and basically keep out of my way. Ok I feel the the XP Luna UI was like something a 5 year old designed with blunt crayons, but you could revert to classic and that worked. (one of the first things that was set in the domain controls was the UI format, Luna it was not)