I applied on campus through our job portal and at the career fair. My interview was supposed to be 30 minutes behavioral and 30 minutes for a case study on campus. The behavioral interviewer never made it to campus and so I only had the case study for the day. My interviewer was a huge jerk. He clearly didn't want to be there, was complaining he didn't get breaks and did not want to be conversational. I started out crunching numbers for their case (you also have to sign an NDA to do the case) but I was super nervous and I couldn't remember how to do certain things. My interviewer was watching me struggle, flipped through his phone, sighed heavily like I was a pain and generally made me more nervous and made thinking clearly worse. Yes, I realize that there are going to be a lot of high pressure situations like this in the working world, but he wasn't friendly at all and clearly didn't want to be there. He continued to watch me struggle and didn't try to help me and as we continued on, he nit picked all my responses. I was told that a lot of time case interviews are subjective and that it's all about your thinking process and thinking creatively, but here he was looking for specific responses and did not like any of my responses or refused to see my reasoning. Also, ZS interviews have a scale of high understanding, medium-high, medium, medium low, and low. I saw him writing out all of my responses as I was struggling to get the responses he wanted. He was not subtle at all and kept sighing and rolling his eyes at me. By the end of it he didn't even do the last question with me and made me feel terrible about myself, to the point where I was close to tears. Worst interview I've ever done in my life, not just because of my own performance but because of the attitude of my interviewer. Also, my interviewer kept bashing other "consulting groups" about how their solutions are no good and how ZS has the best solutions for clients, etc. etc. so he was clearly full of himself and ZS. No other consulting group I've interviewed with has ever been full of themselves or bragged about their accomplishments and have just been humble overall.
Even if my interview had went well, ZS left a bad taste in my mouth and I doubt I will speak with them again.