I've been to many GABFs but it's been a couple years now. Last time, I kind of decided it was my last. For me, it has become too big, and too crowded, and too loud. Really, that many people in an echo-chamber already make plenty of noise all by themselves, without the need for piped-in loud music on top of it. Definitely an event for youngsters. Long lines, people standing there not getting out of the way for people behind them to get a beer. I have attended all sessions, and at least in recent years did not think there were any fewer people in the members-only session on Saturday afternoon than in the other sessions. You don't need to be a member to get in, so members buy their allotment of tickets and then re-sell them.
I also had a Pro-Am beer there once. It didn't win anything, but they served it and we (the local brewery and I) had our names on the board and took some good snapshots in front of it, so that was fun.
The best outside event I attended was the Rare Beer Tasting sponsored by Pints For Prostates https://www.universe.com/events/denver-rare-beer-tasting-11-tickets-denver-J37N60?fbclid=IwAR0LgLAGa3vHVNnEQdqiwom_9t_a-0zCqD2Bo2ISgWvrScgdZLTo6PJqGPU
. It is costly ($200 single ticket level this year), but it includes food, unlimited tastings, a t-shirt, glass, and a free screening if you choose (highly recommended if you haven't been screened...ask me how I know).