Dear Aspirant, all the institutions you mentioned are top IITs. Irrespective of the branch they have excellent placement records and extremely talented faculties. Coming to the question of branch, it should depend on your choice that what you prefer doing, in which field your interest lies, what jobs you want to prefer.

Every IIT has its own speciality. IIT Madras electrical engineering department is best. Mechanical in Kanpur, CSE and ECE in IIt bhu.

I would suggest select the branch in specific instead of IIT because on an average top most package and offers are grabbed by CSE, ECE, IT. Chemical engineering department is good for both Madras and Kanpur. Choose as per your interest and preference. All the best.