If you are looking for a friendly, but professional place to learn Japanese, Hills Learning is the place to go. My teacher, Maeshima sensei, is a native speaker who has a background in linguistics. She can give specific, clear explanations of any kanji or grammar questions one might have. The atmosphere is casual, but serious. Classes are small. My teacher corrects each student's homework and explains errors individually.
I have tried all the "usual" places and none of them offered me what I find at Hills....either in terms of materials, methods or mood. Plus the location is perfect, one block from Grand Central Terminal!
I have met a few other staff members at Hills besides my own teacher. Maki sensei, for example, always takes the time to say hello in the target language, even though I am not her student. People seem to care at Hills Learning....and that makes all the difference.