I have been studying at the school in Cairo for a year, and I would have to say it has been a positive influence on my Arabic fluency to say the least.
I came here only knowing Modern Standard Arabic, and even then my comprehension of it was average at best. Now however I would say that I am very comfortable in both written and spoken Arabic, whether in Modern Standard or in Egyptian colloquial.
The one thing which I think stands out about the school is the class structure. Most students have classes one-on-one in a semi-formal atmosphere, which means you get to learn how people speak normally to each other, rather than learning to speak some really stilted artificial version of how people really speak. You also gain a real insight into Egyptian life and culture as a result.
It is too difficult to jot down just how beneficial my time here has been here, but I can safely say that I have no regrets and would definitely recommend the school to those who are looking for a language school in Cairo