Nova - no-go. Terrible reputation, money issues everywhere.
Gaba - mixed reviews. A lot of people complain, but mainly the complainers are those who just want a good-paying job and not passionate about teaching. There is a lot of complaints about having less lessons if the students like you less, but this is a no-brainer and not Gaba's fault. Gaba does do their contracts differently - you are not an employee, only a 'contractor'. So, no employee benefits like transport costs covered, no company health insurance, no paid time off. It's like a 'teacher-student' matchmaking service really.
Berlitz - Hearing nothing but good things about it, but not enough reviews to know if it's the best or not.
AEON - I keep hearing bad things.
Interac - Keep hearing worse things than AEON, but not as bad as Gaba.
JET - Seems to be the main one people go for. I haven't heard any raving reviews, but I haven't heard anything bad about it. I think it's the 'foot-in-the-door' sort of job placement.
ECC - Seen is recommended or at least suggested a few times, but no idea on what they're like. No bad reviews that I know of. I'm going to be looking into them later this year during their open employment seminar in my city.
I haven't got the full list on me, but these are the major ones I remember from the top of my head. Will post the rest a bit later.
thank you for your comment. There are so many schools here in Tokyo that you could apply, but there is a lot of competition here comparing to other parts of Japan.
Thank you niteelf8413 for sharing that list with us. I am sure that binz also finds this useful.
As I said, there are so many.... so many, but sooooo many teaching jobs here in Tokyo. For me the best website to look for one is this:
I personally don't know much about the particular schools mentioned, so I can't say anything. What you really need to pay attention though is whether they require visa or provide one, whether they offer accommodation or not and pay your transportation expenses. A medical insurance plan would be ideal, but you can always enroll to the NHI sceme and pay your own insurance.