The 200d is a powerful device, and for small businesses with experience with Windows Storage Server 2003 - and the level of expertise required - it could be an attractive choice. It has an impressive array of features and supported protocols, with performance to match. And the built-in REV removable drive is a nice plus, especially for businesses that like to keep some of their data backed-up and moved off-site.
But on the downside, the price of the product is substantially higher than similar capacity non-RAID products and even higher than products such as Buffalo Technology's Terastation and Infrant's ReadyNAS 600, both of which support higher-capacity, more robust four-drive RAID 5 configurations for about $500 less and also include print servers. And the fact that the 200d runs Windows Storage Server 2003 means it is one more system to worry about keeping patched against the continuing stream of exploits aimed at this platform.
SOHO and even many SMB NAS appliances are usually inexpensive, quiet, consume little power and have low maintenance requirements. The 200d, on the other-hand, just feels more like a standard Windows server (although in a relatively compact form factor) with a NAS web GUI front-end bolted on.
Which type of NAS is right for you depends, of course, on your requirements. If you need to support a network with an assortment of client OSes, have sophisticated user and group management needs, have Windows server expertise in-house and cost isn't a primary consideration, then the 200d could work for you.
But if you're budget-minded, have a homogeneous network and just want to get additional shared storage onto your LAN and forget about it, then there are many more cost-effective choices available than Iomega's 200d series.