I installed drupal 6 on Monday for testing. In my first trial, according to my expectation, its new action and trigger are useful and suitable for workflow operation.
But it is not a right time to migrate existing rich drupal 5 web sites to version 6 for me. Some contributed drupal modules for drupal 5 are missing, module developers are busy to porting their code for new version.
And new version might suitable to build new English web site only, because completion % of string translation for Chinese locale is low. Localisation Client is a drupal 6 module provides on-page localisation (string translation).
Currently, I am still starting to code my drupal module for version 5, and will be ported to new drupal version after reaching first milestone of my development.