According to me, IIIT Jabalpur is way ahead of the other two colleges. It is followed by NIT Patna. Here are some advantages of IIIT Jabalpur-
The placements for Mechanical, CSE and ECE are quite impressive. Other students opt for CAT/GMAT/higher studies abroad. The college is just 4 km away from the Jabalpur airport which facilitates more companies to visit the campus for placements. Because of good connectivity to major metropolitan cities of India, the placements are expected to increase exponentially in the coming years.
Campus life is great. You can play Volleyball, Cricket, and Football with your friends till late evening. The college fests- Gusto and Abhikalpan are much awaited.
Therefore, out of NIT Silchar, NIT Patna and IIIT Jabalpur, I would suggest you go for the third one.