Driving Route 66 so flew into O'Hare Chicago, and prepared for colditz stye interigation, instead we were through in a couple of minutes. Whilst in the lounge at Heathrow we got chatting to a Mum and daughter and the daughter said had we downloaded the MPC app to speed through security, I said no and downloaded it. Ticked a few boxes took a photo of my passport, did the same for the missus on the app and then left it till we arrived at O'Hare.At O'Hare we loaded the app and it said follow MPC signs. We then followed the signs to MPC control.....no que. Went into a booth and gave our passports in, got asked where we were staying, how long we were staying, took our fingerprints and gave us a blue form and said enjoy your trip.Had to wait a couple of minutes for our cases, handed the blue form in and walked through the exit then towards the trains. After the stuff I read on Reddit regarding interrogation and looking through your social media I was expecting a nightmare and it was the opposite.