Not the greatest amount of server space but incredibly easy-to-use and a number of helpful features.
License: Free for personal use only
Norton's file sharing service offers you the chance to upload important files to the cloud (5GB free).
The tool itself works very similarly to most other offereings. It installs across most devices, from your Windows or OS X computer, to your iOS, Android and Windows RT mobile devices. The app adds a 'Zone' folder to your system and you can simply drag and drop files into it and it'll automatically uploaded to the cloud, as well as synchronise the files across all of your devices.
The service can also be used to work with others. Users can create links which enable others to view a specific file as well as set up a folders which allow a group of people to access, download and delete the contents.
There are a number of other helpful options that ship with the app that provide you with a bit of security when sharing. You can create links to a file and set an expiry date on the link, say, or a link that'll work for a certain number of downloads