If you had specified the parameters on which you are judging the institute, it would have been easier to answer the question. In terms of quality of education, the two IIITs are better than the three NITs. 

Given below is a brief comparison of the institutes based on various parameters. You can make your decision based on that. 

Faculty:(IIIT Delhi > Top NITs ~ IIIT Allahabad)

IIIT Delhi has the best faculty. Even top NITs don’t come close to IIIT Delhi in terms of faculty. 

Campus Life: (Top 3 NITs > IIIT Allahabad > IIIT Delhi)

The top 3 NITs offer better campus life. As compared to NITs the workload of IIIT Delhi is too much. IIIT Delhi also does not have as many clubs and societies as top NITs. NIT campuses are also bigger in comparison. 

Hostels: (Winning Institute - IIIT Delhi)

• IIIT Delhi has better hostel facilities as compared to any other Govt. college or even some IITs for that matter. In summer you will get air conditioning and a heater in winter at IIIT Delhi. There are also sports facilities like Foosball and Swimming Pool, etc. 
• Other facilities available at IIIT Delhi are quite similar to that of NITs and IIIT Allahabad.

Placements: (IIIT Delhi ~ Top NITs ~ IIIT Allahabad)

In terms of placements, IIIT Delhi matches the placement statistics of top NITs. A student of IIIT Delhi has recently secured a placement package of 1.45 Crore. The average package of the institute mentioned in the question is around 15-17 lakhs (for CSE). 

Location: (IIIT Delhi > Top 3 NITs ~ IIIT Allahabad)

• IIIT Delhi enjoys the benefit of being situated in the capital. The city life, start-up culture, and many internship opportunities are some of the perks of attending IIIT Delhi. 
• Whereas, the top 3 NITs are situated in small cities. IIIT Allahabad is also located in Prayagraj, which does not offer a good city life or enough exposure. 

But whether you will like the campus or not depends on your background. If you are from South India, life in Delhi or Prayagraj may not be that appealing and vice versa. 

Reputation & Alumni Base: (Top 3 NITs > IIIT Delhi > IIIT Allahabad) 

• The top NITs have more recognition among the recruiting companies due to their legacy. IIIT Delhi is a fairly new establishment in comparison. Even though it is growing at a rapid pace, it is still up to the standard of the top NITs. 
• The alumni base of the top 3 NITs is also better due to the same reason. 

If you are genuinely interested in coding, you should choose IIIT Delhi or IIIT Allahabad. Otherwise don’t go for IIITs.

Considering this question, the first thing that can be highlighted is that both of these institutes cannot be compared at all. However, studying IT in IIIT Allahabad is far better as it offers several opportunities, as well as institutional environment and infrastructure to assist the student in their career growth appropriately.

However, CSE at Vellore Institute of Technology (VIT) is not so secure considering the programming prospects and study culture that the student will get at IIITA. This choice is easy enough for the student to make as per their career perspectives. 

The following table gives a brief overview of these two institutes:

Thus, considering the above facts, it can be stated that between these two institutes, the student must go for IIIT Allahabad, as VIT can’t be compared at all.

Unlike many other premium engineering institutes, IIIT Allahabad offers a number of enriching experiences apart from the curriculum. There is a scope of exploring the writer inside you by becoming a part of the literary club and spending your time reading/writing. This has been one of the most successful and enriching ways to spend a weekend.

If your home is nearby, (Lucknow or Kanpur) you have a good chance of visiting home at the weekend. Moreover, there are a number of tournaments and championships also being continuously organized on campus to keep the students active and develop them holistically. There are coding competitions and championships organized too.

Taking a stroll during the nights inside the campus is a beauty of its own. It’s a massive campus with lots of trees which gives peace of mind specially needed for the weekends. You might also want to utilize your time to finish all your uncompleted assignments, projects and other academic related documents.

If you love traveling, you can plan a very nice trip to Varanasi from Allahabad.

One of my friends was a 7 pointer and he got offers from top MNCs even before completing his graduation. You don’t have to worry much about pointer and placement, as there is no straight relation between them. What matters the most is getting a good CGPA. There are several top 5 companies that will shortlist you on the basis of your knowledge. If placement is not important to you, then try to score a good CGPA, which is not tough to get in IIIT Allahabad. It will be useful if you are thinking of going for higher studies.

Therefore, keep the placement worry side and focus on your study. However, having a good CGPA will not guarantee your placement. But will definitely help you in your career.

Yes, students do apply for internships. It is up to you only when do you wish to apply for it. 

Here is an approximate time frame of the whole course which may be helpful for you to understand the internship opportunities offered. 

There are two long breaks provided by the institute during the year. One big winter break in December and one summer break of 2 to 2.5 months in May, June, and July. 

• Most students start applying for internships after the 4th semester, though students applying for internships before this is quite uncommon, but it is not non-existent.
• Summer internships during the 5th semester are offered by recruiters on campus. If any individual receives an offer letter, he/she has to join and complete this internship after their 6th semester during the summer break. 
• During the 8th semester, students also apply for six-month internship programs, for which recruitment is carried out during the 7th semester. Students participate in internships both on and off-campus.
• You can always apply and join an internship during any of the breaks. Tech internships for one month are quite rare which is why it’s hard to find good winter internships easily. 

Summer internships are easier to come by as compared to winter ones, depending upon your skill, abilities, the company, and profile you apply for.

My younger sister has enrolled in the CSE program at NIT and it has excellent facilities for the program. The brand name of NIT and IIT is still more popular for some of the engineering aspirants because they lack awareness. Even my sister thought so before admissions, but NIT ranks #16 on the NIRF Engineering scale, IIIT A ranks #103, and IITs are usually in the top 5 in the same. 

Furthermore, your decision may change based on the following-

• The location of IIIT Allahabad is a factor contributing to its low popularity. It is located in a small village area called Jhalwa. There are no recreational facilities around and the only eating outlets are MacDonald's and Dominoes, which harm in the long run.
• The placement statistics of IIIT A show that it has a good 96% placement rate, but not many top companies come to visit because of the location. Networking is not an issue, but an institute in a developed area would have easy accessibility, lectures by renowned faculty, spots of refreshment; which are not present here.
• The hostels are not very good and those who reside in them, face difficulties related to social outings.
• Another fact of importance is that this institute has only two departments: Information Technology and Electronics and Communication.

You can see below, the comparatives of the institutes:

As you may see, IIIT A and NITs have excellent placement rates. The faculty will be more brilliant at IITs but students are dissatisfied even there. So you can see for yourself according to location, placement scenario, and brand name if that matters.