I have a few friends who have completed their B.tech from IIT (ISM) Dhanbad and Jadavpur University. Here are some crucial factors you must take into account to understand the difference.
By no means a state-level university can outstand a national-level Institute. IIT (ISM) Dhanbad has an edge over JU in almost all aspects. If you score well enough for IIT (ISM) Dhanbad, there’s no point in thinking about Jadavpur University.