I think the slate form factor has been around for sometime...

But the different thing this time around is the software (UI) and the contents available on it...

I've had a few (windows) tablet PC in the past... and there's no denying that you just can't get good experience with an OS that's primarily designed to be used with mouse+keyboard on other form factors.

Good hardware spec isn't a good benchmark of the quality of interaction you get from said device..