I found the Thecus N2100 to be a full-featured box that provides data security, flexibility and expandability with performance comparable to other products with Gigabit LAN interfaces. The box had a few rough edges, but overall, the software was well written. As far as cost, a street price of around $320 seems a bit high for a BYOD, two-drive product.
That said, it was a bit hard to find a device that directly compares to this device, since few have built-in RAID capabilities. For example, the Kurobox HG is a bring-your-own-disk, Gigabit-enabled NAS box going for $149, but it's a single drive unit, doesn't directly support RAID, and doesn't have a polished software baseline. The Buffalo Technology HD-HG250LAN is a Gigabit NAS device that can be found for under $200 including a 250 GB hard drive, but once again, it's a single-drive product and doesn't have RAID support.
For multi-drive products, the $549 500 GB Yellow Machine supports RAID all the way up to Level 5, but I found its performance to be sub-par and it lacks Gigabit LAN support. Finally, the four-drive Buffalo TeraStation isn't available in a BYOD model, and the least expensive of the Infrant ReadyNAS BYOD versions costs a little less than twice as much as the Thecus.
So you'll have to judge for yourself whether the benefits that the Thecus N2100 provides justify its price. As for me, the RAID capabilities of the unit provide peace of mind for data security, and its expandability means that it can keep up with my ever-growing data needs. It's definitely worth checking out if you'd like to step up to a more secure NAS, but your budget isn't quite ready yet for RAID 5!