My fiance had his K-1 visa interview today and was approved!
The process took nearly 3 hours. He got to the Embassy 30 minutes early just to make sure he knew where to go and to allow for any delays. Once through security, he waited an hour to submit his documents, then waited another 10 minutes for fingerprinting, then nearly an hour and a half for his actual interview. He said only 2 or 3 interviewers were working.
When he was called up he was initially asked very few questions: how we met, why we decided to get married, if we had met each other's families, what our wedding plans are.
The interviewer was not as friendly as others have reported here but he was not rude or intimidating either. He congratulated my fiance and told him he would receive his passport and visa by Friday or Monday. Whew!!!!!