IIIT Sri City, IIIT Una, IIIT Trichy, IIIT Kota and IIIT Kottayam are new IIITs. These were established under the Public-Private Partnership (PPP) model. These IIITs, even though new, are a brand and the education quality in all these IIITs is almost the same. The only difference between these IIITs is their mentoring institutes and the institutes where they run or operate.
Hopefully, this will help you make a decision.