So, after several changes in travel plans due to flight delays, my wife did her interview on arrival at EWR. Maybe a 10 minute line (at 5pm) and the interview itself only took about 5 minutes. She's a non-citizen, so I was concerned things might be a little more complicated, but no problems (except for the other folks in line that saw her passport and told her she was in the wrong place...) She did have an appointment scheduled for a couple days later, just in case, but looks like they cancelled that upon approval.