It seems that you have heard the experiences of many successful people who took the postgraduate entrance examination, and basically said so. New Oriental English is very famous, which is of great help to improve the ability to take exams. Wendeng Mathematics is a lecture given by Chen Wendeng, the former head of the Department of Mathematics of Nankai University, and has tutored many students to get full marks in mathematics. Politically, Wenhai is indeed stronger, and their teachers have a clear division of labor and complementary advantages. I have participated in many remedial classes for postgraduate entrance examination in Changsha, and one of my classmates has also obtained a postgraduate degree from the Chinese Academy of Sciences. His views are basically consistent with what is said above.