I was fortunate enough to get an interview in Phoenix, AZ for this position. They had a short phone interview after which they invited me to come on site. Many of my friends interviewed at that location and received a schedule with interview details a week before the interview. Unfortunately I did not get a schedule until the day of my interview so I was going in to the interview blind. I even had to email the hiring manager the night before just to get the building address.
Upon arrival I was told that I was given the wrong building number, luckily I came early and was not late, since the correct building was only a block away. There were four other candidates for the position. We were all given an introduction to the job at the same time, after which we had four private interviews. Everyone was very nice, knowledgeable and laid back. We had a very good conversation with a few behavioral questions in between. The questions they asked were very similar to the ones posted on this website. The only question that was not on the list was "why is your GPA not so great? Why not 4.0?". My GPA is in the 3.6-3.8 range so it is not too horrible. I replied that I had to balance my classes with research which resulted in a couple of B's, however, classes that were applicable to my field of study are all A's. In addition, my research resulted in a number of publications with novel concepts, so at times I had to sacrifice some study time to advance my projects. The interviewer seemed to take this response positively, noting that the job will require balancing multiple important projects at the same time and often requires compromise.
After the interview, I sent a thank you letter as is customary. Since they did not tell me how long it will take for them to get back to me with an answer I waited for two weeks before contacting them again. I did not hear back from them since the interview three months ago. The hiring manager didn't reply to any of my inquiries so I am assuming I didn't get the job.
Note that this experience only reflects on the management style of one group. Many of my friends heard back within two weeks of their interviews whether they got it or not. Most groups will let you know, this was my unique experience.