Which is better M.Sc, MCA or BCA?

MCA and BCA both are preferred degrees for getting IT jobs. Whereas MSC has many wings those can be considered for academic and other science areas. You need to be more precise about MSC stream.

MSc BSc Computer Science is better then MCA BCA combination. It will save you one year. Also MSc CS will give you solid Computer Science theory concepts, which will help your career. However consider Institute also while deciding.