I just bought it - it's really helpful, as I recently bought project5 which doesn't support sidechain compression.
A feature I'd really like to see is a visual graph showing the envelope info that would be outputted - which could be frozen by clicking a "freeze" button. The reason is, it's a bit hit and miss adjusting settings, then recording the automation and seeing what comes out. If DPMPro showed a preview in it's interface it would allow settings to be adjusted before recording the automation. As I said before, the freeze would allow you to view the data without the window constantly updating. Maybe the window could also be set to display 1, 2 or 4 bars?
Just an idea, but it would be extremely helpful