It seems clear that there are some differences between Microsoft's designs and implementations and Apple's. But if you compare, say, DOS, Windows 3.1, Windows 95, Windows XP, and Windows 7, it seems difficult to make the case that Microsoft's changes to Windows have not paid off positively for users on balance over the years. Certainly there have been missteps, but those missteps have, to date, always been overcome over time, and almost never by backtracking to the previous state of affairs.

Perhaps there have been sufficient missteps, though, that people feel they have both license and cause to second guess major changes.

Whether Win 8 itself ends up being successful or not is still an open question, of course. But I will be happy to wager that (A) there will be a major next successful version of Windows, and (B) it will look a lot more like the Win 8 Developer Preview than it does like Win 7.