The concept of IP based storage is rapidly winning me over. The idea of having a device sat on the network, constantly available for any other machine to access or backup data is appealing to me as somebody with a lot of data to look after and a lot of media that could do to be stored centrally instead of on DVD. Similarly, that appeal can extend into the office environment as a means of both backup and data sharing. NAS is by no means a solution for the average home, however, and should stick to offices and the abodes of geeks.
Physically, the Thecus N4100 is spot on. It's small, it looks good, it has lots of pretty lights and it has adequate cooling. The drive caddies are sturdy, meaning you can remove and reinsert them without fear of them snapping, unlike some of the cheaper drive caddies I've come across in the past.
Feature-wise, the N4100 has some good stuff going for it. Active Directory support will be welcomed by net admins, otherwise the 'regular' user/groups system provides ample control over access to the device. The choice of options for RAID arrays is good. Although anybody serious about backups won't do so to a RAID 0 array, at least there's a choice there. I can't see much point in using anything other than RAID 5, when you weigh up the benefits of it against the other RAID modes available with the N4100.