After BSc in computer science if you think that you can crack the GATE/CAT exam then MBA or MSc may be good option. MSC in following fields is good for you

MSc in software engineering

MSC in information technology

MSc in cyber security and data transmission

Top colleges for MSc are-

Delhi university

Anna university

DIAT

Jadavpur university

BITs Pilani

You can go for MBA in following streams through CAT-

MBA in telecom management

MBA in HR

MBA in IT

MBA in business administration.

Top colleges for MBA are-

IIM Ahemdabad

IIM Kolkata

IIM Bangalore

IIM Indore

IIM Kozhikode

XLEI Jamshedpur

I think both the courses are an added advantage to your B.Sc degree, its just your choice and the inclinations of which career you would like to select between management or technical field.

So if you feel you are good in technical aspect then go for M.Sc or else if you feel that your functional aspect is better than go for MBA.