I can install drop box in under ten minutes. I don't have to manage security patches for all the binaries in the stack. My data is available in network edge locations close to me or the people I share it with. I can turn dollars into more storage very easily. I don't have to configure user permissions and groups in more than one place.
Also, what you described is not "sftp + cvs + vps" ;D
Also, what you described is not "sftp + cvs + vps" ;D