I would say the artist formerly known as OS X has never been good. It literally started its life as a half-assed NeXT attempt and has only gone downhill from there. There's still a "Services" entry in the file menu. .DS_Store files are an abomination. Mac OS thinks it knows better than I do about which software I'd like to install. Plist insanity that makes the Windows registry look pristine. GUI inconsistencies across every surface area... I'm curious what you like about it, because other than font rendering (which it does well), I can't think of anything positive.