Avantages
Visa They set up an apartment (and car if needed) for employees If you're lucky, very lucky: Free teacher's housing (house quality isn't great though) Full time contracts (paid health insurance, etc)
Inconvénients
The biggest problem is that there is no room for career advancement. The foreign country experience might look decent on a resume but while others are furthering their careers, teachers at Interac are spinning their wheels and setting themselves up to return home to work at a McJob. It's something to really consider. You'll be in a completely dishonest work environment, both in the schools and when dealing with Interac. The Japanese call it "Tatemae," and as you move up the ranks from baka (stupid) to just somewhat KY (ignorant of the situation) you can try to play along pretending you enjoy your job as they pretend that you're valuable. Even the foreigners that get promoted to managers are still very replaceable and they know it, so they pass all their stress down to the teachers. My MC looked like he'd aged a decade in two years. Eventually it will kill your soul if you have one, and when you wake up one day with an inexplicable urge to do something terminally unkind to yourself you'll realize "Aha, I've had the quintessential Japanese worker experience" and it will be time for you to go home.