Citrix's hat in the arena is Sharefile, and offers all the expected bells and whistles when it comes to file sync and collaborative sharing. This includes making it easy for employees to share data with direct integration to the Windows desktop and Microsoft Outlook support, and being able to directly edit Office documents on mobile devices.
To bring flexibility in where data is kept, Sharefile sports what it calls StorageZones which allow IT to use local CIFS-based (Windows networking) shares, off-site cloud services such as Amazons S3 and including those managed by Citrix, or a mixture of the two. Authentication still happens with Citrix's servers during logins, which is different to Spideroak or ownCloud where this can be managed locally.
The exception is if using the new Restricted StorageZone feature of the latest version, where as long as a locally managed StorageZone is being used administrators can optionally keep encryption keys within the enterprise.
One useful feature -- especially given the propensity for employees to use cloud storage services they're familiar with as we covered in the introduction -- are Connectors. These allow users to access data on their personal cloud services like Dropbox or Google Drive through Sharefile itself, while giving administrators control over which services are used and to what extent. This way IT can ensure compliance to have company-related data to moved from personal cloud service accounts to Sharefile if necessary, or define permissible cloud storage services that for example a client may use.
As you'd expect with Citrix there are extensive reporting features including the ability to track user activity, remotely lock or wipe data on mobile devices should they go missing, and set expiration dates on shared files. All transfers are encrypted with 256-bit TLS or SSL as is, of course, data at rest with AES 256-bit. Daily backups and in-built anti-virus are also included as part of the service, as is customised company branding if desired.
Platform wise, beyond Windows desktop integration, Sharefile can be accessed anywhere with a browser, though iOS and Android native apps are also available. Users can sync files across all their devices, share files or folders individually or among teams, and set permissions all while on the go. If you're already running with a Citrix Xen virtualisation solution, Sharefile is also designed to integrate with the virtualised desktops with Xendesktop, remote application delivery with Xenapp, and MDM management using Xenmobile.
In terms of cost Citrix differs in that bandwidth counts towards storage limits, though this assumes use of Citrix's StorageZones. Small businesses can go with the Professional or Corporate packages which start at a minimum 10 and 20 users respectively at up to US$100 a month for 20GB. For larger companies and the Enterprise feature set pricing depends on scale, as well as if Citrix-managed or locally managed StorageZones are used, and if annual or perpetual license models are selected.