MAT Scores

The decision should be based on objectives that you set and the expectations.
The placement setting could be similar and not much difference in terms of companies that come for recruitment.
The fee structure in SSN is very competitive with two year program cost at Rs 4.5 lakhs inclusive of single room hostel accommodation.
SSN admission process is very strict and no student with less than 80 percentile MAT score will be offered an opportunity for GD/PI. SSN also insists on academic consistency and students with history of arrears generally do not qualify for GD/PI irrespective of their high scores in admission tests such as CAT/XAT/MAT/CMAT/TANCET.
This makes your peer group strong and consistent.
SSN also enjoys the location advantage as Chennai is the best place to pursue MBA kind of program. Needless to mention, SSN comes from a historic corporate background of Dr Shiv Nadar Foundation (Dr Shiva Nadar is Chairman HCL Technologies) which is investing close to USD 1 billion for education initiatives in the country. The institutes are run in a open way with students getting the choice of academic learning.
Make an informed choice, attend GD/PI in all the three institutes, observe the differences in the process, evaluate your options and then make a decision.
Wishing you the best.