Hello,
I think Lucknow Centre of Gravity Classes will be the finest for IIT JEE coaching. My relative studied there and he picked up a lot from coaching in Gravity Classes. Firstly we wanted Gravity Classes because it was turning over consistent results and Lucknow Centre branch has experienced faculties. Also, they focus a lot on concepts and having concepts clear is very important. The questions provided for practice were of all the levels and exams were conducted on a regular basis. That helped him in having a good practice in real exam like environment. He was getting good guidance and study material.
Gravity Classes is the best coaching institute for IIT-JEE. Faculties are excellent. They are handing out remarkable results year by year. You should visit the branch. People are cordial and you will get valuable guidance on how to start your preparation for IIT JEE.
You can visit their website for previous year results