I and my wife worked there for three months in 1999. We had our passports confiscated so that we could not leave. When we asked for them back, we were told that they were being held at the local government offices (the name of which escapes me now). Being a Russian speaker, I was able to check the foreign labour law and, after many visits to the government offices behind Kaminsky's back and armed with the pertinent parts of the legislation, we were able to get our passports back.

We then walked out in the middle of a class and caught the next train to Sheremyetyevo (while Kaminsky was on a "business trip")

Course wise, the school didn't actually seem that bad. But the exploitation was unbearable. Keep away.