HKS definitely provide better career trajectory for its brand name. It would also have more diverse students for networking and knowledge exchange. You have to weigh how much it would cost to go to HKS, and if you can command a salary high enough after that to recover the "cost". If you have the money, go for HKS.
I am a current MPA student, was interviewed last year. It was a case, I was given time to read it, the professor (interviewer) asked me question about the case. No questions about myself, but some others had questions about their past professional experience & etc. All the best!