It completely depends on what kind of events you like to conduct in the future. When it comes to the NIEM Pune, the focus is more on corporate events and this, in turn, would give you more corporate and/or wedding planning experiences in practicality.

Whereas, as far as NIEM Mumbai is concerned, it focuses much more on the show business and exhibition aspects of event management. In the end, it entirely depends on what sort of events interest you more.

A friend of mine has worked with both the Pune and Mumbai branches so my knowledge comes from experience.