Well - had to be done. I needed to get my site updated from Drupal 5 to 6 in order to implement some better features and in general keep up with what I do for clients. It was also useful to go through the upgrade process on an existing site to get used to the pitfalls.
Overall it wasn't all that bad, but I did have to reimagine how I wanted to deal with some views, and recreate some of them from scratch. I haven't had time to really dig into the design, but this had to come first and setting a deadline helped move things forward faster.