Using the live demo is the best way to get a feel for DSM 3.0. Synology has taken an different approach from other NAS manufacturers (although LaCie's new GUI is somewhat similar). The screenshot below shows DSM 3's "desktop" style GUI with three apps or widgets open.
I set the browser width to 1024px wide and you can see that the "desktop" gets crowded pretty quickly. You can resize some windows, the Storage Manager, for example. But the Control Panel doesn't resize and eats up a lot of room on the desktop. So you'll probably be minimizing it to the bar at the top of the screen or quitting it entirely between uses.
Synology DSM 3.0 Desktop
The gallery below hits most of the highlights of DSM 3's feature set.
In all, Synology's DSM 3.0 has features to suit both consumer and business applications. But it needs to continue to enhance its business features to stay even with QNAP and NETGEAR.