I downloaded the trial version and ran it on my personal site and on a client's site. It seemed to work very well. The only problem I noticed is that on the client site, the menus are fly-out DHTML menus and it was hard to get a grasp of how the user was using those from the data that I was being shown. I also would rather it tell me that no one or <1% of users have clicked a link rather than showing nothing at all for that particular link.
Overall, though, I was very impressed. I need to dig more into the tagging and such, but this could make a nice addition to the WebTrends stats when we do website audits for clients or potential clients.