One more data point: applied for NEXUS on June 4, conditionally approved on Aug 14, snagged an appointment Aug 20 in Detroit, showed up to appointment 1.5 hours early, was taken in immediately, whole thing lasted 10-15 minutes. Got approval email by the time I got back in my car.
Many thanks to everyone in this thread (and the NEXUS info thread)! Was lurking for a while and everything here was super helpful.