My experience was exactly as described in previous reviews. Allowed in 15 minutes before the appointment. Security station inside hte door. Escorted elevator ride to the visa section. 2nd security station. A short wait to be called to a window to submit the documentation. Sit back down unti the rest of the appointees had submitted their documents, then called to a 2nd window for the interview.
The interviewer was friendly and disarming. He never even asked for primary evidence of our meeting within the last 2 years. The only hiccup was that I needed to get certified copies of beth's divorce (originals were not acceptable)
I returned once I had them (no appointment required), went straight through to the 1st window, and was approved on the spot. Visa in my hands 2 days later. This step was by far the easiest and least stressful.