I signed up for Global Entry and couldn't be happier. I highly recommend paying the extra $15 for Global entry ($100 vs $85). For the extra $15 you get a much quicker customs experience via a kiosk at airports. Supposedly they are working on it for some port terminals as well. Port Everglades didn't have the kiosks but they had a different lane for Global entry (you had to have your card), which was super fast.
They have kiosks now at MSP. And, ALL travelers use them. It is the most painless customs/immigration procedure ever. There were a LARGE number of kiosks replacing the relatively small number of humans they used to have. You print out a piece of paper from the kiosk, and then hand them to a human. Quick. I'd say we were outside the airport, with out bags in hand, in less than 20-25 minutes from landing. Sure beats the hour I spent in customs the last time I entered the US (same airport).