Both MBA and Mtech are really good as career options. Both of them have value.
MBA prepares you for different roles and generally expands your knowledge in non techincal areas, whereas Mtech focus on increasing your techincal skills. It takes your technical skills to next level.
MBA has more scope in finance, banking, consultancy and others, which maybe techincal. Mtech gives you opportunities in academia, research and development and technical fields.
So i would suggest you to choose according to your interest. It matters the most.
All the best!