Both IIT Mandi and IIIT Delhi are reputable institutions in India and offer high-quality education.
Located in Himachal Pradesh, IIT Mandi is known for its strong focus on research and innovation. IIIT Delhi on the other hand is located in the capital city and is known for its focus on both research and industry collaborations.
IIIT Delhi is definitely a better option in terms of CS education. IIT Mandi despite having a school of computing and electrical engineering lacks a good faculty pool and there is hardly anyone in computing. IIT Mandi has more focus on electrical engineering than CS.
Both institutes were established around the same time period yet IIIT Delhi is way ahead of IIT Mandi and is expected to remain so in the near future. IIT is a central government institute while IIIT Delhi is a state government institute. Despite this, IIT Mandi has failed to improve in terms of infrastructure, while IIIT Delhi has completed phase I of construction for about 900-1000 student capacity a long time ago. Additionally, IIT Mandi lacks faculty, so comparing other factors like research, projects, and industry connections is illogical.
Don’t join IIT Mandi just because of the IIT tag rather, look at the bigger picture. It ultimately depends on your personal preferences and academic goals.