Arrived at 7am, first in line. Most other people there were for Non-Immigrant Visas.
Appointment was at 8.30 but was seen at 8.15 at first, about 10 minutes sorting out paperwork and making sure all was in order. Very friendly and relaxed.
45 minutes later was called to the main interview. Young smart looking american man who was very professional but friendly. Asked the expected questions and within 5 minutes he said he was pleased to approve the visa.
Waited 10 minutes in line to pay for the courier, £26 for the before 10am service. Was out of the embassy by 9.35
Come prepared and all will go well, no need to be nervous if you have everything in order and are telling the truth.