We're not in DYS (yet, maybe someday!) but I can answer the others. The most challenging part is by far school. We've had a rough ride and we're about to move schools for DS in hopes of finding a smoother path. Our attempt at getting everyone on the same team failed miserably.
The benefits of an HG+ kid? I have a boy kind of like Kriston's. He's very rule-driven, very logical and likes structure. He is rarely in trouble for disobedience because if I say "please do ___ because___" it nearly always happens. By rarely, I mean like maybe once every few months! He's never been a tantrum kid partly because he learned to communicate early. It's not all wine and roses, he needs constant stimulation or begins creating his own, which is generally not pretty! But overall, parenting has been relatively simple.