I started using FDT 4 today. I was asked to do some speaking on FDT so I figured I may need to get a little more familiar with it. Long story short. It is way easier to set up with existing Flex projects that you may have been coding with eclipse / Flash Builder. I was up and running pretty quick.
One thing that was bugging me was the package explorer. The tree did not nest children of packages like in Flash Builder. I thought that this was a setting that the powerflasher guys backed in but come to find out it is a simple setting in the package explorer that you can change. Rather than typing you instructions I make a quick video to show you how to change the setting.