iCloud is great for swapping files between Apple-approved programs, but it doesn't do much else. QuasiDisk is a file manager that allows you to store whatever you want on your device and gives you access to iCloud's folders.
To sync files, QuasiDisk lets you set up a private FTP server, use iTunes File Sharing, or tap into the hidden iCloud folder for syncing. As a simple file manager it gets the job done and gives you access to files you need quickly and easily. If you're using the hidden iCloud folder trick to store files, it's the only way to access them on the go. QuasiDisk is $1.99 in the iTunes App Store.