While the original questions had to do with mechanical differences between GC and other, having gone to GHC, Origins, and GC in the last year, bit of perspective in terms of general activity.
If it isn't already, I have a sense Origins will become a much better experience. You can transmute much more easily. Everything not TD related is closer. You don't have to fight for runs as much.
But, it depends a bit on what sort of "energy" you prefer. Gen Con is hectic in ways the other aren't. Maybe your group isn't rushing around from one thing to another, but a lot of other players are. We did TD at GC this year after: 12 hours of RPGs, 8 hours of RPG, 4 hours of LARP + 5 hours of special event. We are tired, possibly cranky. Meanwhile, GHC did 7 runs of TD and TG and it was rather chill as even a back to back was still playing the same game in the same area. If you like intense with more discovery with filled out parties, then GC may be better.
I look forward to Origins as an opportunity to get some more runs in of N2 and N3 (do hope N1 is an option though I prefer N2 and N3) with a much less frenetic vibe and I don't mind if the parties have fewer than 10 players. It is hard to feel the same, though, with having already done dungeons with not having done them.
On a more mechanical note, I thought one of the dungeons improved massively between GC and GHC last year where the other got much worse. Didn't do Moongate nor Dancing at Origins so don't know whether I would have enjoyed any of the four possibilities more at Origins.