I think a good way to judge an operating system is how you need to deal with it when it’s messed up. Like last night: I needed to do an archive install, then do some updates to airport and to safari. This morning, I spent half an hour (because I was lazy) redoing software updates. That was it. Everything else was still there… iTunes, address book, bookmarks, desktop picture.
Windows would have necessitated me doing a complete reinstall that would have erased the rest of my system. Such was my (monthly) experience of Windows ME.
You can’t expect an operating system not to get messed up. But you can expect its developers to have prepared properly for such an occasion.
Now, to continue my day as usual, with the cats having duly scolded me when we returned home.