Yes, I have tried DBE, but I have to say that my best results are with Gradient Exterminator in CS5. I am using a trick: when I select the DSO, inverse the selection, then run GE 3 times with increasing fineness of the correction.
I just ran this on 14 images on M104 stacked with PI and it came out well (for me).
I think I will try DBE again now that I have a bit more experience. I wonder if I can deselect the DSO also in PI.
I have some underlying issues insofar as I have changed my imaging set up so I have to collect some new lights to try all this. I am in a very LPed area new San francisco...