QNAP was one of the first to launch AJAX based configuration software and since continued to build on its success. I really hate to make statements like 'best available' or 'best that I have used' in a document that will be updated from time to time when features are added or removed, but the QNAP software just flows so well. I am not really sure if it is just how fast the software is when transitioning from one page to another, or the nice graphics. Maybe it is both, but my personal favorite setup software at this time is what you saw today.
As it sits right now QNAP also has the best add-on packages for their NAS servers. I particularly like the app that runs the Usenet downloads; to each their own. Web designers will really like being able to install the web server application and add-ons that are available for it.
Once you get started installing packages it can quickly get out of control and you need to know the limits of what all you can run on the hardware you purchased. If you are planning on taking advantage of going all out with the extra software, be ready to purchase one of the higher end models or at least look into upgrading the amount of RAM in your NAS.