Oh well, once more the discussion going on about data accuracy of the big statistic vendors. I've seen a few Hitwise graphs before and went through a few demos with their reps, but never could really warm up with them since their data wasn't really useful to my purposes.
That said, I think Hitwise, Compete and all the others can draw a nice picture of your site and your competition. Do I care if they are 100% accurate? Certainly not. Do I think they are better than the diluted Google Trends tool? Yes. Are they worth ten thousands of dollars? Not for the most businesses, but for the one's that are in highly competitive fields or target a wide range of users, the tool is definitely worth every cent.
Do we need to have this discussion again? No....b/c there are way more important things to fix first. To start.....it would be awesome to get rid of PIs and focus more on Display Visibility.