Thanks for asking. The event was awesome, there were definitely a lot of candidates and business school admissions officers present. I think that the QS folks told me that 750 candidates signed up, and 300+ actually turned out. Probably about 60 schools were at the event itself.
Unfortunately I didn't get to meet any BTG members. Next time I'll try to give an earlier heads up, and also plan a meeting spot for a quick meet-and-greet.
Very much recommend the event to current MBA applicants!