Having successfully deploying a reasonably high traffic Drupal website, I can tell you that the boost module is like mana from heaven.

The only issue that I have found with the boost module is when you have blocks that update data in real time, or are interactive, a good example being the poll module. This can be over-come by writing a custom module that pulls in the content via AJAX. This isn't particularly difficult to do. I bet that it could be fairly easily generalized, and if I had mounds of spare time, I would do exactly that.