Nothing like London then.
You queue outside round the bulding in most cases. If you don't have your letter you don't get in.
You get inside they issue you a number take anotehr £10 off you, you sit waiting to hand your forms in, they take your forms. You sit again, waiting till you get called to an interview window. They ask you a few questions and hopefully let you know the outcome and send the Visa in the post. (Yes, they checked the SEVIS fee.)
Average time : 4 hours - I was lucky and got in and out in 1 1/2 hours.