From the MSDN Blog:
It looks cool, a mixture of Dropbox, iCloud, and Google Docs. If they add an OS X app for this, with 25 GB of free storage, Dropbox will get a run for it’s money. Google Docs too, as useful as they are, they look like crap, at least with Office they would look decent. iCloud is not threatened by this as much in my opinion, because the integration of iClod with iOS and OS X is something that SkyDrive will not have (unless Apple changes the way things work in a big way).