Other than iCloud Drive and the Existing Documents and Data, what possible danger is there to iCloud data, ie. email, contacts, bookmarks, photo stream, etc. in installing the public beta. I will be installing on my 2012 MBA, not my main machine, the iMac. But I don't want any iCloud issues with my daily usage. I don't run iTunes or iPhoto or Aperture on my MBA. Those libraries are empty. I only use the MBA for M$ Office, web, email, etc. and all docs are synced via dropbox. Thx.