Pros
Provides you with a working visa and a job title that looks impressive on a resume. I have a few good memories of cultural events.
Kontras
Firstly, no one actually works for "JET" The JET Program recruits participants who are then hired by local governments or boards of education. As others have mentioned, this means that conditions vary from place-to-place. It also means that JET itself has zero power to resolve workplace issues. So, this review is very specific to my workplace at the time. I worked in a government office for one of the largest prefectures in Japan. That may sound ideal, but the weird social pressure that government employees face in Japan permeated the place. Local governments have to maintain an image of frugality (i.e., not spending tax money on upgrading facilities for staff like toilets and desks) but staff members themselves have absolutely zero incentive to truly perform. Once you become a public servant, you'll basically stay one unless you commit a crime (that is, if you can handle a 40 career in an environment with toilets and offices that haven't been upgraded since the 1970s.) I had almost zero work to do during my time there. Each week I'd have around half a day of work spread out over five days. This sounds ideal, but quickly grew old and made me feel guilty. I couldn't exactly sit there just browsing the net either. Other CIRs had tried creating events or new initiatives, but they were all turned down. In the end we gave up. There was also some bitchiness about how much the CIRs earned considering the work we did (we did earn more per month than some employees, but didn't receive bonuses, so it was about even). All in all, it was a toxic work environment. The cultural events were sometimes interesting and the groups holding them genuinely had good intent, but most events did more to maintain stereotypes than overcome them. 99% of them were organized by outside groups, so it was hard to provide true input. Additionally, many events were on weekends and although there was a time off in lieu system, it didn't apply to time spent traveling. Considering the size of the prefecture, this meant I could lose 1.5 to 3 hours of my weekends traveling. My direct manager should not have been working in international relations. She would have been perfect in the tax division, but nowhere else. She was widely disliked by the majority of the staff in the office. I would submit reports to her which would be returned to me 10 or 15 times. This was completely demotivating and led to other staff members sticking up for me on occasion. I also worked as a Prefectural Advisor (PA), providing advice and peer counseling to foreign English teachers (ALTs). Some had severe mental health issues and should not have been living overseas, let alone somewhere like Japan. I enjoyed being a PA, but it was sometimes stressful and on one occasion devastating (due to a suicide). It was also frustrating dealing with young, self-entitled ALTs with zero common sense who refused to accept cultural differences ("If I can wear jeans to work in America, why can't I do it here?" "Well, because you're a public servant and Japanese society sees public servants differently from how they're seen in the west, there's an image to maintain." "But, why should I have to go and buy new clothes for work out of my own money???") Overall, although I have a few good memories as a CIR and it helped improve my Japanese skills, I can't help but look back over it as a waste of time. I don't feel even mildly nostalgic about that period in my life.