Vantaggi
1) Ideal for those who only need to make a few extra dollars; 2) Foreign managers seem very reasonable people, and; 3) Very little stress in classes (as long as you can live with the, "anything is okay mentality).
Svantaggi
1) They don't tell you at the interview that you'll probably get from only between 1 to three lessons per day which means you won't be able to survive off this job only; 2) Some schools aren't very easy to get to. If you aren't a Japanese speaker/reader you might have some anxious moments (occasionally); 3) When you arrive at your school, the Japanese teacher will probably tell you, "Anything is ok", which means you have to come up with a lesson plan really quick, and; 4) every month the company has some off days, which means you won't have any classes.