We had a great experience at our visa interview. Every person we encountered was super friendly, from security to the first person who screened us to the guy that "interviewed" us. The interview itself was only two minutes long, with very basic questions and an interviewer with a good sense of humour :-) And he didn't even ask to have all my carefully collected evidence of our relationship! He was convinced based on our previous paperwork and rapport on the day.
The only downside was that we had a 3 hour wait. We were warned about this by the first person, who recommended we go out and get breakfast before coming back to wait for our names to be called. They were apologetic about the wait and explained it was due to being down staff members that day.
Watching the pre-screening of the other people coming in for fiance visas, it was clear the consulate staff were mostly concerned with ensuring noone was feeling stressed about it. They were all very kind.