hi,

its an completely an personal choice to whether do an master of business administration course or an master of technology course and there is no better than you can knows which is best for you and in which field you will have more chances of being successful .
generally the master of technology course is for the people who are technically strong and were as the master of business administration course can be done by any one who has completed there graduation from an recognized university or an college in the country let be an mechanical engineer or any other graduation from any field .
keeping everything aside if the master of business amdinistartion course has some advantages when compared to the master of technology course specially in india ,provided if the master of business administration course is done from an good college and not some b grade college ,some of these advantages are as follows :

1. In India the salary offered to an master of business administration course graduate is far far more than what is being offered to an student from the master of technology field .
2. also the master of technology course is having some respect only if done from some bets institutes in the country like the Indian Institute of Technologies and the National Institute of technologies and if done from any other colleges there is no value where as the master of business administration course if done even from the b grade colleges gets salary equivalent to what an master of technology graduate can make even by doing his course from the best colleges in there area of specialization.
3. most of the times its always seen that genially an MBA graduates goes to the management and the m tech people have to work under an MBA graduate even though they are far senior to them just because its always an trend in the various companies that an technical person is never an good manager and hence not given the management roles .
4. also the MBA graduates can change there jobs at will from one company to other even though that companies work in completely different areas of operations where as that's not the case with the m tech students because there area of specialization gets set after the completion of there m tech and they can work only in that area and hence they have limited options while changing the companies or jobs .
5. also the environment in an MBA college is far better than than the m tech colleges and hence the studying there is more fun and interesting,while its boring in m tech colleges .

so all in all its far better to do an master of business administration course than a master of technology course in our country .you being an mechanical engineer can go far operations management course which would be an ideal course for you .