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.

IIIT Guwahati is known to have conducted a successful placement session in the 2019-20 records. Other than that, since it has its mentor institute, which is IIT Guwahati, its placement reports seem to have a consistent hike.

Several companies have successfully placed students from IIITG. Some of the companies where various students achieved their placements are as stated: Instahyre, TCS, AlgomaMills, TechJect, Distill, Datakalp, StatWig, Antares, Kuvera, Kirusa Tech, EdgeTensor, Cohesity, Wipro, Infotrust, Cerelabs, HumbleSchool, Vassar, Nagarro, ThoughtWorks, Guavus, IBM, Adapt Ideation, Nayan, Aptude, and several others. 

The placements for 2019-20 are as briefed below:

You should, without hesitance, opt for IIIT Guwahati. Hope this helps sort your doubts.

If you think that you can work under technical giants later in years of study, then you should go for VIT. However, if you want to pursue your field of interest, and choose a likewise job scenario, then undoubtedly, you should enroll in IIIT Guwahati. 

There are various differences between both the institutes for B.Tech ECE. Let’s walk through most of them:

Approaches of VIT:

• VIT has a gigantic campus and is considered top-notch by students. You will most definitely enjoy your four years course period in VIT.

• VIT, other than that, has balanced boys: girls ratio.

• VIT is known to secure you a corporate job sooner than IIITG. This is seen at least in the current scheme.

The following table shows the placement statistics of both institutions:

Approaches of IIITG:

• IIIT Guwahati is comparatively a very new college. 

• The placement record is not 100%. If you however have the necessary abilities, it is only then that you will get placed. There are unfortunately no mass recruiters here, unlike VIT.

• IIITG is renowned to motivate you to think and implement your theories in places not most people have thought of before. VIT clearly missed out on it.

• You will find that the questions are seldom asked in IIITG examinations. In a nutshell, you are likely to find not any repeated questions in any course throughout the B.Tech course, unlike of course VIT.

• IIITG tremendously focuses on the research sectors.

VIT is a reputed institute that is known to get you a job in the placement. If you’re willing to enter the job sector soon, join VIT.

IIIT Guwahati is an institution that will become the leading institution of the country in a few years. They have a healthy student-to-faculty ratio. Almost all the assistant professors have a doctorate. 

• The institute is operating from the heart of Guwahati, from a building with a 2000sqm of area. It is completely air-conditioned, with backup power, state-of-art laboratory equipment which is on the Assam Textile Institute campus. 
• Students and faculty stay together in a flat complex in the city where they have hired more than 70 flats. 
• The campus is over 70 acres of land, about 4 km from the airport of Guwahati.
• It is growing steadily. In the coming years, it is going to be among the best institutes in India. 
• It has also been given the title of the institute of national importance and is a centrally funded technical institute. 
• According to NIRF, IIIT Guwahati is the best IIIT under government and the 4th best after Hyderabad, Bangalore, and Delhi, which are private institutions.
• The academic curriculum is the best among all the IIITs. 
• The present director has been the director of the Institute for 10 years. Under his leadership and experience, the college is doing exceptionally well. 
• The faculties are the best. You can approach the professors any time you want.

As far as placements are concerned, this institute is one of the few which release their actual placement data.

My brother has studied here and as per him, fee waiver scholarships are actually not a part of IIIT Guwahati. My brother has not encountered anyone in requirement of a scholarship program held by IIIT Guwahati. 

At the same, contrary to any scholarship programs, there are several students in the institute who have availed themselves of education loans for further studies. They are managing circumstances at their personal levels, and none of their financial weights are provided or funded by the institution itself.

You can get in touch with the administration and get hold of any crucial information. They can tell you about any scholarship program actually run and funded by the institute. They will provide you valuable information more than anybody in the student area.

In a nutshell, IIIT Guwahati does not receive any known funds from the government for meeting recurring expenditure (or in particular, any running expenses).