During job, you will be learning how to implement your theoretical knowledge for real time situations, but to get the more knowledge of designing/research aspect of your current work, one should go for the masters. It will be difficult to prepare for the entrance exams (GATE) while you are on job. We suggest that if you would like to get the feel of job, qualify the GATE exam in the final year and join the company thereafter, as GATE score is valid for two years. MBA after job will be preferred, as you will try to work on real time challenges during MBA, which you might have faced in your job.