Our appointment time was 7:00am. We had to wait about 2 and half hours. Once you get through security it's a big waiting room with windows and you sit and wait for your number to be called.
The actual interview only took about 5 minutes. We were leaving the embassy at 10:00. Our interviewer was very sweet. She asked us a couple of basic questions; where I live, where my fiance lives, how many times I've been there to visit him, our plans for the wedding, and if I brought anything else I wanted to share with her (I had made a photobook through shutterfly of pictures of us) She quickly looked through it and said our visa was approved.