What is the difference in quality between IIT Bombay, NIT Trichy, and BITS Pilani?

I have friends in all the 3 institutes so I happen to be the right person to answer your question 

A friend in NIT Trichy told me that the lectures are boring and the professors are incapable of delivering the concepts in a skillful manner. Most of them are hardly interested in teaching and offer no individual assistance. Only a few exceptional professors help you here. 

Meanwhile, my friends at BITS Pilani and IIT Bombay were all praised for their respective institutes. 

• These institutes offer better job opportunities and exposure in the form of scholarships and internships.
• The research culture at these institutes is yet another reason to prefer them over NIT Trichy.
• The crowd quality of these institutes cannot be compared to the crowd at NIT Trichy. IIT Bombay is the best IIT and attracts the highest JEE rankers while BITS Pilani with its no-reservation policy only accepts the cream crowd.
• These institutes provide a path for their students to inculcate and harness their talents. NIT Trichy fails to realize the potential of its students and only focuses on theoretical learning. 

So yes there is a huge difference in the quality of education and opportunities offered by the aforementioned institutes. However, in the long run, it’s your skills and talents that matter.