Well, the Arexx port for workbench was extended for 3.9. If you are a bit of Arexx nut (like me) you might find the extras useful. I honestly can't remember the changes from the top of my head. There was Amidock which is one of the nicest docks around and a lot easier to manage than some others. AHI is installed for you aswell. One of the boing bags installed ASyncWB which lets workbench multitask. This is a very welcome feature as you are no longer locked when deleting files and stuff. As for stability, I never noticed my system being more/less stable than when I had 3.5 installed
