Why are IIITs such as IIIT Hyderabad, IIIT Delhi, and IIIT Allahabad so underrated?

The three IIITs mentioned by you, namely IIIT Hyderabad, IIIT Delhi and IIIT Allahabad have no connection with one another. Only IIIT Allahabad is a member of a collective known as the IIITs.Out of the remaining two, IIIT Hyderabad stands for The International Institute of Information Technology Hyderabad, and IIIT Delhi stands for Indraprastha Institute of Information Technology Delhi.

All these three are prestigious institutions and I would disagree that they are underrated. IIIT Hyderabad is very difficult to get into. It has high cutoffs which are at par with some of the top IITs. IIIT Hyderabad is considered as one of the best institutes to study CS. The same is evident through their CS placements, a number of entrants in GSoc, and their participation in competitive programming. As far as IIIT Delhi is concerned, the institution has grown tremendously in the past few years. It has cut offs comparable to NSIT and DTU. 

All these institutes are relatively new and have the tag of “Research Institutes” attached to them. These might be an obstacle to their fame. This is because in India, students choose those institutes that promise the best industrial career prospects and not the ones driven by research.

However, because these institutes are research-driven, the quality of their course content is top notch and they attract some of the best faculty. This also works to increase your overall development and opportunities in the industry. The popularity of these institutions is thus growing rapidly. 

Therefore, all three institutions are really good choices to pursue your higher studies.