Well, I'm here right now and it's in many ways great. Safe, convenient, lots of delicious food, I have a decent-sized house 30 minutes from the center so it's not like being in a shoebox. A homogenous, cohesive society that keeps things clean and where you very rarely see anyone being randomly aggressive is so good for mental wellbeing. It's only tolerable if you have a decent job that does not require you to take the morning trains, though. That's a hellish experience. And I'd really not want to be an English teacher or work in recruitment. Horrible dead-end jobs.
Tokyo is by far the best big city I've ever lived in, and you can get away from the feeling of being in a metropolis pretty easily. That said, I'm probably going to move to Kansai this year, because I'm a bit bored of Tokyo and like the historical sites in Kyoto.
