As a postscript to this thread, when you walk down the hall to customs at DFW and are unlucky enough to be standing behind 3000 people, as I was last Sunday and you happen to have Global Entry, just cruise on over to the side and make trucks for the far end of the customs hall.

I've been in this hallway when staff were like, "hey, you can't cut in line!", but more recently they all seem to be on board with asking you, "Global Entry?" Now that's not to say that I didn't hear a lot of grumbling from the non-GE folks who probably stood in line for three hours...

I cleared customs in about 10-15 minutes, most of that was the time it took me to walk through the customs hall.