Hii Sala Hudeen..

There is not much difference between them.

IITans have an advantage of brand value.

And you will be surrounded by great minds in the country which gives you a positive energy and pushes you(That depends on with whom you do friendship as you can find bad people too in IITs).

And ofcourse IIT professors have a good experience, publications and good knowledge.

Recommedation letter from an IIT professor have more value.

If you go abroad you will be preferred more.

Hope you got the difference. All the best.