Best language school in Tokyo

I studied at KCP for 9 months, and I will recommend the school to anyone serious about learning Japanese. I had friends in other language schools around Tokyo, but from what I can gather KCP is by far the most academically rigorous.
The workload is not for everyone though, and if you just want to come to Japan to slack off and have fun I don't think this school is for you. My favourite things about KCP were the fact that most of the student population are Chinese and Korean, so you're forced to from the beginning to speak Japanese to them to communicate and you get to learn simultaneously about their culture while learning Japanese.
Also, there are field trips every term and they really serve the bring the class together. Everyone would always look forward to them, and though you might not be able to communicate well with your classmates, you can create great friendships. If it wasn't for KCP I wouldn't have met Tete, my Chinese friend, who during the term break took me to her hometown in Chongqing in China and gave me a tour. KCP is also like a school; there are clubs and it's in a dedicated multi-storey building with a cafeteria. Highly recommend.