Judging by the fact that nobody actually chooses to use Microsoft products unless they're forced to, this is going to flop about as hard as Windows 7 Phone did.
Really, they suck of late. XP was a turd until SP1, but after that, decent. XP with Office 2003 was good, but Windows 7 still has too many Vista-isms for enterprise use, and Office 2007/2010 are just laughable. Microsoft strongly discourages their enterprise customers from deploying 64 bit Office 2007/2010, they can't even make the 64 bit version properly open files created with 32bit Office 2003/2007. And people wonder why Open Office can't support all of Microsoft's formats properly.
They'll be all but extinct by 2020.
/rant