I'm a big fan of the informal get-togethers. Personally, I like them even better than the official big annual gathering. (Which historically have been located all over the map. They have not been held solely in Reno in the past, even though DITD is located in Reno. I think they have tried to move it around so lots of people can attend. What they'll decide to do in the future, I have no idea, of course. Anything can happen, and usually does...)
I find that the smaller gatherings tend to make it easier to find people close to us to build friendships--and more regular playdates!--with. We have several ongoing friendships built upon DYS connections, and I really value the opportunity to get to know these wonderful, fun, wise people!
We're going to two of the informal meetings this summer, and many of the people we're seeing are people we befriended at other informal meet-ups. The informal ones also tend to be more conducive to an introvert's comfort, IMHO. I LOVED seeing all those kids and parents in one place at the national meeting last year, and it's a marvelous opportunity, but it was also a little overwhelming to me and DS7. Smaller groups fit us better. YMMV, of course. HG+ extroverts would have to be in hog heaven at the DYS annual meeting! It's really quite amazing!
The biggest helps to me personally have been the contacts with other GT families and the wisdom and fun gained from those connections, and the educational and parenting support and advice from the consultants. I like the feeling that someone has my back and we're not in this alone. It's like insurance more than anything.
The free online seminars with experts in a variety of fields are also a pretty neat bonus! They have seminars for kids and parents, and they're a pretty amazing opportunity.