Interac and Nova are two seperate companies that operate in seperate ways. NOVA has typically specialised in meaningless English Conversations "schools" which consist of little more than a foreigner reading from a text book to a small group of people. AEON, GEOS, ECC, etc have the same style.
Interac is part of a new trend in using foreigners, referred to as a "dispatch" company or hakengaisha in Japanese. Basically contracts are given to the company from the Japanese Board of Education and the company hires, contracts and pays the teachers. Generally the positions are for public High, Junior High, and lately Elementary schools. In the past teachers tended to be hired directly by the BoE or the schools themselves, but this has changed in the last few years.
Theres alot of dirty tricks that have come to light within this area, especially this time of year, as they will advertise for positions that do not exist, simply to have names on the books to be able to compete for contracts (contracts from the BoE are finalised in April, sometimes barely a week before school begins again). Another dirty trick is to advertise high salaries, only to tell applicants that "due to lower than expected contracts from the BoE" they will be paid less, sometimes up to a third below what was advertised. (Note - I have a friend who works for Interac, who did the former [advertised for positions in Saitama, lost the contract, and so all these people who were told they were working in Saitama now were given a weeks notice that they will be in other prefectures] but were true from the start about the salary levels - but until my friend receives his pay I'm withholding my judgement).
Yet even after all that most people come here, do the work, have fun and don't have any issues, but its worth knowing what can go wrong, plan for the worst and not have it happen
