Hey,
Both CUSAT(Cochin University of Science and Technology) and Madras Christian College are good at their own place when it comes to Master of Arts in Economics. It is entirely your call as to where you want to study from.The infrastructure is good and the faculty is great. The campus life is also good and i depends upon you as to how you make use of the resources being provided to you. The placement cells of these colleges are also good.
Hope this helps.
Good luck.