Currently attempting to hire with a choice of one of two take-homes. I've successfully navigated other take-home exams, including Jobcase's. This take-home, in comparison, was very wide in scope (asked to more or less design the entire company's infrastructure). On one hand, it meant I had the chance to read about a lot of different technologies. On the other hand, I was asked to explain each component in excruciating detail, when I had already spent nine pages answering the questions that were actually asked of me (and where my answers were largely brushed aside in favor of the things I Didn't Do).
There did not seem to be clear communication, between the four interviewers, regarding what the take home exam actually entailed. Based on my (admittedly short) experience at ZMAGS, I'd be concerned about the team's ability to provide constructive feedback, and my product manager's ability to take responsibility for their role in properly scoping projects.
I also have significant reservations about the potential working environment. One of the engineers interrupted me mid-sentence to ask questions like "what is a support vector machine" that had nothing to do with the design interview or with the qualifications of my prospective position. I don't understand why employers do that kind of thing - is it meant to gauge how prospective employees respond to pressure?
The same engineer apparently tried to "trick" me into answering too difficult a question by posing a question as if I was supposed to get better time/space constraints than I actually needed, and then lectured me on not "overdelivering" when I tried answering the more complicated question. Once again, this kind of condescension does not bode well for the potential working conditions as an engineer. If I'm going to deal with higher-ups who, e.g., purposely give vague project requirements and engage in victim-blaming afterwards, it gives me reservations about the company culture.
In my personal opinion, there is no need to make the interview process so adversarial. An interviewer's job is to communicate as clearly as possible, not to "trick" the interviewer into answering the wrong question. It would also be easier to communicate the take-home's expectations if it were changed to the design of a single subsystem with more concrete I/O requirements.