There are a couple of users of PDN, here. Look in the both this board and the General Discussions board on thread discussing PDN specifically. There might even be a PDN tutorial, though I am not sure.
Still there's a stronger core of GIMP users here, and am not sure if PDN is capable of using scripts to automate various complex functions like GIMP, if not, you've got many capable user's like RobA that use script features extensively. That alone makes GIMP more powerful then PDN.
Again PDN might let one use scripts as well - I don't know. I'm only a minor user of GIMP, relying on Xara Xtreme and hand-drawing/scanning for most of my work.
Still there are a few PDN users here.