I knew about Global Entry but hadn't gotten around to making the application when I arrived at O'Hare after a Jumbo Jet from India. I watched the people on my flight breeze through Global Entry while I waited in line over 45 minutes with hundreds of passengers from the jumbo jet who looked ill and were coughing - A LOT.
They had the passengers in the lines for US citizens to help speed their entry, so it might have been an unusual situation.

I got my Global Entry card right after that.

Can you combine the trip for your interview with a day of shopping or sightseeing? I'm an hour, 15 min away and made a day of it with a friend. Well worth the time and money.