IIITDM Kancheepuram is an institute of national importance and it has an advantage over the other two institutes as both the institutes are IIITGs in PPP Mode. The bill to declare PPP mode as institutes of national importance is still pending in parliament. 

Here are a few pieces of information about the CSE/IT in the campuses mentioned in the question. 

IIIT Guwahati:

The institute started in the year 2013 and has a strong CS department with a good number of experienced faculties. 

• Prof Gautam Barua who is the director of the CS department at IIIT Guwahati was also the director of IIT Guwahati from 2003-13. With his immense experience, he aims to build the department strong. 
• Coming on to the curriculum of CSE/IT, it is well designed to suit the growing need of the industry. The intent here is to complete all the core subjects in the first 6 semesters so that students can choose the type of industry they want to get into. Like in the 4th semester, there is a subject called Computer Network which is generally a subject of 5/6th semester in other institutes. 
• In the CS department, IIIT Guwahati has come up with the Ph.D. program as well. 
• There are many advantages to join IIIT Guwahati but only a single disadvantage is there i.e. Location. But if you love to travel and nature, Guwahati is a place for you. 

IIIT Sri City: 

• The number of faculties at IIIT Sri City is nearly half as compared to IIIT Guwahati. 
• They also have MS and Ph.D. programs which indicates that they are also very active with regard to research. 
• They are being mentored by Prof. UB Desai who is also the director of IIT Hyderabad and a pioneer in System and Network Research in India. 

Both the colleges have their advantages and disadvantages. You have to analyze which is better for you to pursue B.Tech in CSE/IT as per your parameters. Good luck.

ENI stands for Electronics & Instrumentation Engineering while EEE is Electrical & Electronics Engineering. Having known some people studying at both these institutions, I can say that BITS Goa is better than NIT Surathkal.

• In terms of infrastructure, BITS Goa is obviously better than NIT Surathkal. 
• Better companies visit BITS Goa campus than NIT Surathkal. 
• The course curriculum and the quality of academic projects are also better at BITS Goa. 
• The faculty at BITS Goa is also top-notch.
• In between the two branches, both are almost the same barring a few subjects (3 subjects to be precise). 
• The course load, placements, and projects all are similar between the two. 
• As these are core branches, getting placed in the core companies is going to be difficult at either of the institutes. 

Finally, I would say that ENI at BITS Goa is very good and actually might be a little better than EEE at NIT Surathkal.

You should go to IIT Gandhinagar. That being said, if you have obtained the CSE degree course at Gandhinagar, then the most probable rank you ought to have is under 1800, since the closing rank is around 1800–1900. In that case, you can opt to go for other old IITs’ by compromising with the branch. You will get far better students at old IITs, which can be a plus side to your personal development and further enhancement.

For the most part, the problem with the new IITs is that they lack to provide a greater established alumni network and good infrastructure. However, since IIT Gandhinagar was established back in 2008, you can expect decent infrastructure and facilities. 

CSE in NERIST is not a great option in terms of money and time. As one of my friends studied there, here’s what I got to know about it:

• The syllabus hasn’t been updated to the latest needs. 
• Some of the professors have no teaching experience. They are more focused on students mugging up rather than learning.
• You will be taught languages that are no longer properly working in the industry. 
• The labs here are messy and no the library is too small to accommodate a large group of students. 
• The local Arunchali students tend to boss around and threaten everyone.
• The non local teachers also fear the local students and hence they give them better marks, to avoid the commotion. 

Moreover, the environment is not academic-friendly. The placements earlier were very bad but have improved eventually. CS has few such good teachers who really care about their students and how much they are actually learning.

You should choose the branch as per your choice and interest. It would be advised to not choose CSE just because it is the highest-paid.

Secondly, if you are pursuing CSE, you will need a laptop with a good internet connection. You cannot always be dependent on labs. You can also join online courses offered by CODING BLOCK, CODING NINJAS, EDx, MIT, and many other MOOCs to get good at programming.

It is not necessary to always look for a brand tag if you really believe in yourself especially when you are studying CSE. Placement opportunities are available in reputed companies such as Google, Amazon, and many more by your skills in the definite field.

iMTech is an integrated course offered at IIIT Bangalore which includes a 5-year BTech+ MTech program. It is not possible to compare a 4-year BTech course with a 5-year Integrated MTech course.

• If you want to pursue MTech after BTech, iMTech at IIIT Bangalore is a great option as you will save a whole year. However, if you don’t want to pursue BTech, you should opt for IIIT Allahabad.
• The course curriculum and faculty at IIIT B are excellent. On the other hand, at IIITA students are quite frustrated with their faculty.

Based on the above facts and the conversation I had with some of my friends and colleagues who are pass outs from IIITB and IIITA, I would advise you to choose IIIT Bangalore with closed eyes.