Hey there

It actually depends on your passion and interest. But honestly it will be very beneficial if you'll do MBA from top 20 B schools because a minimum of 14-15 lakhs is average salary of an MBA from top B schools. Though fees is high but it's not an issue bif you'll get good package. Mtech from IITs or IISC in material engineering is not that worth doing as compared to other branches. But at last its your choice and by doing mtech it will be cheaper and you can get job or you can study further for research as well this it's best part.

Good luck