What are the ranking of the IIITs?

My brother is from IIIT Delhi so I will be able to help you out with your question. Let me clear you everything about IIT’s.

The question arises which is better and why (Top 5 IIITs) 

1. IIIT Hyderabad is the best of all IIITs and can be compared to other IIITs. It was the first IIIT to be founded. It admits students based on their performance in JEE Mains Paper I. This institute does not have any reservations. Furthermore, it provides a B. Tech in CSE. The placements are excellent. This is the only IIIT that outperforms all NITs. 
2. IIIT Allahabad: It was followed by the establishment of IIT Hyderabad. It is one of the best institutes for offering an undergraduate course in B. Tech (IT). If you are unable to secure a seat in Hyderabad, Allahabad may be an option. The placement is good.
3. IIIT Delhi is growing at a rapid pace (due to faculty and its location advantage). The faculty is the reason for its high tuition. Placements are improving every year. They follow the same guidelines as IIT-Hyderabad.
4. IIIT Gwalior is good for students interested in coding or computers and does not qualify for the above three IIITs. This institute is accessible through CSAB.
5. Bangalore's IIIT. Since last year, this institute has been offering a B. Tech + M. Tech (dual degree). This institute has been extremely beneficial to research. This is ranked lower because one can always get his M. Tech/M.S. from a foreign, IITs, IISC Bangalore, and other good institutes. You have to apply separately for this institute too.

The rest of the IIT's are still developing and are considerably new. These have an upper hand among the other IIITs due to their educational experience.