Choosing an MS or a PG Diploma depends on your needs and perspective. If you are looking at the value and overall stature of the degree, then honestly, the MS course is a better choice. It is academically more reputed while allowing you to get into different educational programs like PhDs. It may also help you immensely while applying for jobs. PG diploma courses are more about practical and job-oriented specialisations, which may help with employment opportunities in specific fields.