The interview at the consulate went relatively well. Our appointment was in the afternoon. We got there early, but we were told to wait outside as they do not let anyone into the consulate early.
There was 2 security checks that needed to be done. The first one at the front door. They confirmed the appointment and then did the usual metal detector check and led us to the elevator.
Upon reaching the right floor we had to go through another security check and then waited. We were called about 15 minutes later.
At the first window, the consular officer looked over paperwork and told us to take a seat again. We waited for another hour or so before we were called to a second window where the actual interview took place.
The interview was very basic...asked how we met, how often we've seen each other, confirmed when the wedding was going to take place etc...
I believe the total interview time was about 10 minutes.
After the approval we waited to see window 1 again. This time they took my passport and paperwork and told us to come back the next day to pick up the K1 Visa.
The next day...there was a long line outside the consulate. I went to the security desk and told the guard that I was there to pick up my visa and he let me up right away (a big thanks to the visajourney forum for this tip).
I was in and out of the consulate in about 30 minutes.