I rarely use Automator anymore. I have a few workflows hanging around, but I can’t think of the last time I approached a new solution in Automator. KM is much more intuitive to me, maybe that’s because I am used to it. The KM support forum and wiki are fantastic. Modern solutions can usually be found by searching, and if not, the group is very responsive.
Some pros for Automator: It’s free. Folder Actions. Ability to create stand-alone apps. Watched Folders.