"Skydrive won. (Accessing it via safari at skydrive.com) Prior to this latest revision, skydrive would finish BELOW last place. It was awful. Folks would stop testing it. Now, it seems to be the winner. It seemed to allow us to do more, format more, AND it managed the workflow by allowing the student to share the documents with the teacher. No dropbox issues. No email issues."
Check out Jim's full post, the challenge itself, and the comparison of the tools.