The old web site (and the pages for each of the various divisions) was to be charitable, a little creaky from a visual appearance and information design (i.e. it was hard to find stuff I was looking for) point of view.
Now they have a content management system that provides a real nice unity of design across the site. The tabs along the left and the top of the page provide a clear path to all the content I can imagine wanting to get from the site.
The one downside is that for most people this site redesign means they will have to update their bookmarks to get to that page they tend to visit while they should be thinking up ways to improve reference service.