There are plenty of NAS options on the market; many of the two-disk offerings concentrate on personal storage but the StorCenter ix2 combines very good read/write performance with a mix of tools that will be useful for businesses as well as power users at home.
You can use the StorCenter ix2 to share storage in the office and let people access files via Iomega's cloud proxy, and you can manage local and remote users separately.
Support for cloud backup – from Amazon S3 to Flickr to IP cameras – complements tools for syncing content to and from local devices. This makes it possible to bring different storage options together to roll your own backup system.
You have to do all of that in the web console. Even if you install the Iomega Storage Manager software you will still need to do most of the setup and administration through the web interface, which doesn't organise the wealth of features particularly well.
Unless you buy a unit with an empty drive bay, upgrading to larger drives is problematic (not least because only two models of drive are qualified to work with the StorCenter), so your options are adding an external USB drive or buying a second StorCenter.
A great little NAS for the small office with a wide range of features, from sync features to remote access, and fast performance.