They may have changed the interview process since I was a Corps Member, just as a quick caveat. There were a few rounds of the interview process (I hope I’m not misremembering the order: written application, phone interview, I think a second call - but possibly that was just informational for the next round, and these culminated in a day-long group interview. During the day 1:1 individual interviews also took place (separate room, independently from the group). This interview day required some preparation: designing mini-lessons / materials that we brought and executed (taught to the “class” of interviewers and each other - the other interviewees). We also completed group tasks while the interviewers observed how we interacted and contributed. I believe they were looking for leadership qualities (which does NOT mean competitively dominating everyone else, it is more about contributing thoughtfully and positively, the ability to get along with & motivate each other to problem solve, etc. I recall thinking that the interviewers were noting whether our participation was a means to help guide the task toward completion.
I’m marking this as “difficult” in the sense that it was intensive, and creative, and geared toward determining whether you’ll fit with not only the very specific vision/mission for the org but also whether you’ll be able to handle the reality of the job itself, working in the most underperforming, impoverished schools in the US (which is of course not easy, it was a much harder learning curve than I’d expected and I’d studied this closely in college). So I don’t think “easy” (eg a phone screen) or “average” (eg 30 minute conversation w/ HR touting your skills) applies. But it wasn’t “difficult” as in unpleasant, it’s actually preferable to an easier kind of interview because you have a day’s worth of opportunities to actively *show* (rather than just trying to tell via resume or standard interview) all of the qualities that make you a great fit!