I have a GPR on the used bike I bought this past year and after a decade of saying "no way" to having steering dampers I'm sold. Being from eastern PA and riding in a club that puts on a "rocky enduro" (Moonshine Enduro) and now living in Colorado I love riding rocks and didn't care if there is any front wheel deflection as I'm used to it. I also rode a lot of South Jersey enduros and did not have any trouble in the deep "sugar sand" whoops either. What the damper does for me is very simple: It makes the front end more precise in its steering so I put the front wheel exactly where I want it and it stays there. Furthermore, at the end of the day, my old and out of shape body is a lot more "fresh" allowing me to ride longer distances more safely. I don't even notice the damper while riding fast, tight, woods trying to keep up with the younger riders. So, if for nothing else, the damper may be a good safety device!
Eric