Hello student, 

IIIT Guwahati and IIIT Kancheepuram are both highly esteemed and prestigious universities that are sought after by aspiring students.
There really isn't much difference between these two as they are the same institute only in different locations.
The faculty in both are highly experienced and punctual, the infrastructure is good in both, the placements are provided to the students, internships are also provided by the college to the students.
IIIT Kancheepuram was set up in 2007 whereas IIIT Guwahati was set up in 2013 so this gives IIIT Kancheepuram an advantage as it already has a well-established reputation among companies which attracts more of them to offer jobs to the students. 
Both are equally good institutes and you need to decide which one is better for you based on location and facilities that you want.
Based on the ranking among all IIITs, IIIT Kancheepuram is ranked above IIIT Guwahati based on their overall reviews.

Cheers!