Got AP (new, first time) from Baltimore today. I had originally applied with VSC (RD: Nov 1, ND: Dec 5). I had with me I-485 receipt copy, 2 pics, letter from employer saying I needed to travel on business, letter from me saying I need to travel. They asked for last I-94, past H1 visa stamp in passport. Luckily I had old passport and I-94 copy with me.
Logistics: I went very early, at 6:50 AM and was first in the line. They open at 7:30 and I was allotted to an officer immediately. Place got crowded around 8:30 - 9:00 am onwards so I recommend people get there by 8 AM. But they don't have a fixed number of people and do not turn others away. It took about 2 1/2 hours to get the document ready. The officer I got was knowledgable and courteous. My only complaint is that later I noticed my AP is valid for 6 months only and not for 1 year as I thought/wanted. Anyhow, by then I was fed up and left rather than go through the whole process again. Note: they will only issue EAD if it has been pending at VSC for over 90 days, they did not let me submit an application. All in all, good experience.