Most of the people I interviewed with were friendly and engaging. I was contacted via LinkedIn based on skills present on my profile, and met with the person contacting me. First round was just a basic behavioral meeting.
Second round was a case interview which on the whole was not too difficult, just sifting through a lot of data and telling a story with the information to interviewers.
The third round, after being called back post-case interview, was overall a negative experience. I believed that since I had been through the case interview and had been called back that the rest of the interview process would be goodness of fit. The third round felt like a first round interview; lots of questioning my choice to interview with the company - overall, it felt negative and unprofessional. Furthermore, I had been contacted by them to begin with, so the way I see it, we needed to both decide we would want to work together.
Then, on top of all of this, two weeks later, after having officially applied online, I was notified by their email subsystem that I 'would no longer be considered for the position.' Thinking this was strange, I contacted the employee who had made initial contact with me, and they told me that they had not made a decision and that this email was a mistake. Since contacting that person about the email, I have yet to hear anything from them.
Overall, I am surprised at the hiccups along the way in this process. From what I have read on Glassdoor, most have not experienced this type of process.