I don't know what it is like now, but hubby's first time around was a breeze. We were asked very few questions, and submitted very few pictures. Neither of us really like having our pictures taken, and the man doing the interview was satisfied with the few we submitted.
Then we decided to move to the UK a few years later, so when we came back to the US, we had to go through the process again. The second time, we did DCF, but I eded up coming back to the US before it was all over, due to a glitch in his medical requiring a TB test, which came back clear, but in the meantime they 'lost' one of his samples halfway through testing... anyway... long story short, that time he was on his own for the interview, and it was a breeze that time too.
I won't say they would never ask the deep dark questions, but I would guess they can sense honesty and would only bring out the big guns if they felt it was necessary.