I agree 100% with Dottie: we're in DYS largely because of the contact with parents and other HG+ kids. Sharing experiences and resources that work for other families is really nice.
Realize that there are informal, regional get-togethers planned beyond the big national one. Having access to other HG+ families in your area is nice for playdates, too. I made a really good friend through DYS, and there are several more friends whom I "e-met" here first and then got to meet IRL because of our DYS connection. These are lifelong friendships, I think, because we have much in common and we speak the same language.
And my kids have made friends, too. Oh yes, the kids...
I joke, but it's really true that when we're with DYS familes, I CAN focus more on my own conversations because my kids are happy and connected with the kids they're with. They have plenty of non-DYS friends, too, but socializing always seems somehow more relaxed and EASY with DYS families. It's hard to explain, but you know it when it happens. Everyone just seems to exhale and feel at home. It's really nice.
I'd also support what Dottie is saying about not knowing what the future brings. I think of the other services and resources that DYS offers as insurance. If I need them, they're there. And it's just nice to have a consultant asking how things are going a couple times a year, even if my answer is "They're fine." It gives me someone who knows what they're doing to bounce ideas off of if I want to.
Finally, there are also online seminars for both kids and parents with experts and educators. Lots of good opportunities!
They also offer financial aid if you need it. While need is a factor, they are not solely need-based.
It's free. All that's required is that you fill out the (long!) application. There's really no risk and lots of reward.