Unless it is a very specialised MSc such as Embedded Systems or Nano Electronics, it may not be advisable to do an M.Sc. In any case, both and MSc and M Tech invariably take four semesters. In fact most MTech programmes can be completed in one and a half years, unless you are doing it from an European university where all MSc programmes are of a two-year duration.

More over, in the job market, an MTech degree is considered more relevant and appropriate than an MSc degree, especially if you want to enter the academic field, where the opportunities are plenty if you have an MTech degree. A PhD in engineering would also be easier to achieve if you move further. So if you are interested in higher studies go for an M.Tech.