First of all, YOU CAN BRING YOUR MOBILE. I read that it wouldn't get past security but other people had it, and you need it to entertain yourself. You're in for a lot of waiting.
So I got there and went through security. Then I walked to the side of the big building and this English receptionist looked at my DS160 and gave me a ticket number. I went in and waited and waited ages. The ticket system is a bit daft. They flash a number on a screen so you have to always be looking at it in case they call you.
I went in at 10am, and I wasn't called until around 11:20am. Finally my number was called so I went up to the ticket window and an English man looked at the DS160, my passport, and fiancee's financials. The guy was really straightforward and friendly.
Then I sat back down and waited ages. Eventually I was called and I saw an American lady behind a counter. She asked how we met and when we met in person. Then she asked me about how I liked Pittsburgh and what book I was reading (Three Men on a Boat). I thought we were just getting started so I started pulling my folders out my bag, then she said "Okay your visa is approved." I was like "Wait what? You haven't looked at my stuff!" and she laughed. I must have have a look of total shock on my face.
She said the passport will be up to 2 weeks. The delivery people (DX) will text me when they've received it.