Yes, between fingerprinting and interview it was 7 and a half months. Interview was pretty straight forward. Appointment was at 2:00. I entered the office at 2:00, got into the room for the appointment at 2:15 and was done by 2:30. 6 very basic questions on US civics and history, remaining were mostly confirming name, address, phone number, background on kids, parents (whether they were citizens or not etc).
Compared to the process taken for H1B or Green Card, overall this step is a piece of cake