Lot of negative reviews floating around the web, but its not so bad IF you have everything in order. Make sure you double, triple check your forms before you go! Any slight mistake will mean you have to redo the forms. I would say plan an extra day as back-up, because there is a good chance they may ask you to come again if something is wrong.
Do not rely on using their computer system. Complete everything at home and come prepared. First of all, there will always be someone that is using the computer (Lawrence location only has one computer). Secondly, while I was there the website kept giving errors. Some guy tried like three times to complete his forms but the connection was unstable and the website kept crashing.
Go like 15-20min before the office opens. There is hardly anyone there. Reps were friendly to deal with. It also helps that you deal with them first thing in the morning when they are fresh and not in the middle of the day where they could be cranky after dealing with lot of people!
It is a hassle going through BLS, but at the end of the day we got our document in the timeline they said we would.