I went through all the rigamarole to get a grand gathering number for our big trip last december, only to discover that everything I wanted to do was already booked.
And this wasn't christmas, it was for the first week of december when Disney's relatively uncrowded.
There was literally *nothing* available six months out.

.
So, except for some big cumbersome round pins that said "grand gathering" that we never wore (they weren't disney pins that go on the lanyard, just the round flat kind with the dangerous spikes on the back), it was a waste of time.
And it took SO much time to get the darn number in the first place. The website for it stunk, too, absolutely no functionality at all, I always had to call the "special number", and then half the time whoever I got on the other end had no idea how to book grand gathering stuff. I ended up calling my DVC number and they actually knew something, but still couldn't help...
