I applied for Global Entry 2 days ago (Wednesday). I got "conditionally approved" last night to schedule an appointment. I logged in this morning and found available appointments at IAH as early as next Friday and nearly every day after that had dozens of available time slots.
Also, the building where interviews are held is no longer at the actual airport. As of June 17th, they are temporarily doing them in a building just south of the beltway near IAH. That should make getting to the interview much easier.
I know this thread is 7-8 months old, but y'all had me nervous about getting an appointment. I was getting prepared to use the apps or services that y'all mentioned. I guess things have slowed down or they staffed up.