I have friends in all the aforementioned colleges and thus am writing this answer based on collective experiences only. From the reviews of their respective colleges, I arrived at the conclusion that IIIT Sonepat is the best option among all these. 

IIIT Sonepat fairs are better than the aforementioned institutes in terms of infrastructure, placement fees, etc. Here are a few strong reasons to choose IIIT Sonepat

• Sonepat enjoys a good location advantage being located just half an hour away from Delhi.
• Located near DU IIT Delhi and other institutes, you can easily enjoy their fests.
• IIIT Sonepat is located in Delhi,  the educational hub so it offers better coaching opportunities.
• IIIT Sonepat has an excellent growth rate in comparison to other IIIT's.

Moreover, judging by my friends' experiences, the preference order I can up with is

IIIT Sonepat>>>>IIIT Surat >IIIT Vadodara>IIIT Kurnool

IIIT Vadodara should be your preference. It has an excellent placement record along with a top-notch coding culture. The no of GSoC selections is at an all-time high. Students of the institute are actively engaging in competitive coding.  

IIIT Vadodara placements 2021 concluded with the highest CTC of INR 43.5 LPA. The average CTC offered was INR 11.53 LPA. Amazon, ICICI Bank, Mathworks, Code Nation, etc. are the major recruiters for the institute. 

My friend from school is an alumnus of IIIT Vadodara and he is of the opinion that IIIT Kurnool is the best choice of the three aforementioned institutes.

His reasons are as follows:

• IIIT Kurnool is better than its Vadodara counterpart because the former has a campus that is permanent. It is, however, one of the newer IIITs and its coding culture is still developing.
• IIIT Vadodara is superior to IIIT Surat and IIIT Sonepat because the coding environment of these institutes is highly competitive. Its students graduate with placements that are better than the ones offered by many NITs.
• IIIT Vadodara, even though being older than Surat and Sonepat, lacks a supportive and responsible mentor. All the achievements made by the institute are owed to their students.
• IIIT Sonepat was established one year after IIIT Vadodara but students of the latter institute get more exposure due to the Gujarat factor. Location is a big factor and paramount in determining the future of the institute.
• IIIT Surat started in 2017 and so obviously it will take some time to make a name for itself. It only has the ECE department. The institute is mentored by NIT Surat and a few professors of NIT also teach at IIIT.

My friend’s preferred ranking is: Kurnool > Vadodara> Surat > Sonepat