First interview was a behavioral interview that I did fine on. I was fairly confident in my answers and myself. I prepared by using the "star method" and I'd suggest others do the same. I was pretty much prepared to answer every question they asked me without having to pause to think too much.
I made it to the final round interview a couple weeks later in Richmond. I drove there (they will reimburse your gas mileage ~$.55/mile and $75 in meals I believe) and they put me up in a ridiculous hotel. You get to go out with other interviewees and current employees the night before the interview and ask all the questions you can think of to help prepare yourself. They'll pretty much tell you that you're not really competing with anyone but it's really your job to lose.
The final round interview consisted of another more brief behavioral interview, case interview, and job fit interview. I dropped the ball on the case interview I'm pretty sure. It wasn't necessarily difficult, mostly algebra. They want you to talk and communicate through it which I did. I just had a brain fart trying to solve a multi-variable equation (substitution! substitution! substitution!).
Overall, the experience was good. The culture is young and you can tell that everyone really enjoys their job. The campus is wonderful and it looks like a great place to work.