Well, I've been watching the gp32x forums for literally years, since long before the gp2x was released - i used to think about getting a gp32 but was never quite convinced and there was always a better cause for my cash. I think I even got a forum account a couple of times to ask some questions, but I think it then got disabled.
But I joined this forum straight away, and I find it much more professional, easy to use and easy to read. I know gp32x is where the community started but it really isnt too straightforward to use, or easy on the eye, and when I used to browse it childish flame wars and off-topic comments were absolutely everywhere, and it was generally just kind of annoying to try and get information from. Having said that, I haven't really been on it too much lately.
I don't know what the developers of the pandora think, but if I was in their position I would want to present a really good image to newcomers - let's face it, the crowd over at gp32x are pretty much all pandora buyers already, and to keep this project moving new customers are needed. And however big a part of the project, the usability and friendliness of the forums are important for a business venture like this. There is a freshness about these forums that gives the idea that they are tidier and easier to navigate, there are less threads because it is new but each one contains exactly the information you need. And there are links to gp32x when it has superior information for something, if it's really needed.
I'm not critising the gp32x forums, its great the community that has built up there, and without them we wouldn't have the pandora. But I think it's the future, not the past, that is important. And I think that perhaps both forums are needed in some way.
I think a lot of the reasons people aren't using these forums are:
+ They are already members of gp32x
+ This forum is no longer linked to from the pandora home page (AFAIK)
+ Other reasons already covered here