Hii aspirant..

If we compare Jadavpur University and BIT Sindri then surely Jadavpur University is much better college comparatively. Jadavpur University is one of the best colleges in India for engineering and is having very good and NIRF ranking.

College wise I would prefer you to go for Jadavpur University every time when compared to b i t Sindri.And I can assure you that yes you will get their awesome placements, faculty ,alumini network ,infrastructure. 

Although if you are interested in mechanical engineering then you can go for bit since the department you choose for your engineering is going to decide your future job and career.

Hope it helps. 

Best of luck