Comparing 2 IITs is illogical as every IIT is unique in its own way. Because of the difference in the duration of the establishment, one might have a better alumni network than the other. The same is the case between IIT Kharagpur and IIT Bhilai. Both are excellent Engineering colleges, yet the former being the oldest IIT has a much more elaborate alumni network. 

The distinguishing feature includes some eminent alumni like the CEO of Google Sundar Pichai, Jeetu from the Kota factory, Gaurav Taneja aka flying beast, Biswa, etc. IIT KGP is well known for its amazing coding culture. It has great faculty and societies that help in the holistic development of students.