According to the reviews of students, following is the rating given to the colleges.

IIT, Guwahati

• Academics - 8.1
• Fees - 8
• Placements - 7.9
• Infrastructure - 9
• Social life - 8.7

NSIT

• Academics - 7.7
• Fees - 7.6
• Placements - 8.3
• Infrastructure - 6.9
• Social life - 7.6

According to this data, go for IIT, Guwahati!

Good luck! :)