Mover.io is a site that helps users migrate from one cloud backup provider to other. It copies user's data from one account to another account without the need for downloading any software to user's computer. It's service is super fast and they are very reliable in their field.
About this site
Transfer anything between anythings. FTP, SFTP, Dropbox, Box, Google Drive, Microsoft SkyDrive, SugarSync, WebDAV, SharePoint, Amazon S3, MySQL, the list goes on! No installation required.