Dear,

If you want CSE/IT/ECE, then top IIIT's like IIIT Hyderabad, IIIT Delhi, IIIT Bangalore, and IIIT Allahabad are very good in terms of course structure and placements. IIIT Hyderabad is considered to be better than all nits. IIIT A/B/D is also better than almost all NIT's and is growing very rapidly. The campus life at top NIT's is definitely better but academics is considered to be better in IIIT's. Also, the cutoff ranks have been steadily improving for the IIIT's and some NIT's have become less preferred than before.

IIIT B and H don't have reservations at all. IIIT A also does not have a reservation for State people but has a caste-based reservation( Though IIIT D has a reservation for Delhi students). All NIT's have a reservation for students of their state because they are managed by their respective state governments. The Coding culture at IIIT's is usually better than that at NIT's and they don't have to study common subjects which are taught in the first year at IITs or nits.

Hope this helps!