If you try to download large files from OneDrive Personal you might discover that your downloads time-out. A possible reason for this has been discussed here: http://onedrive.uservoice.com/forums/262982-general/suggestions/6325783-remove-the-file-size-limit-of-2gb-for-syncing
It is being worked on, but no fix is eta.
OneDrive for Business is not affected by this
So if you are looking to back up Your OneDrive, try to limit the files you Download to 2GB, and do multiple Downloads.