Guyzz it really does not matter which insitute you join its just upon your choice and comfortability.No insitute can make crack IIT.
It depends your hard work and time you give to your studies.i am a current narayana students and I have been studying there since 10 months.what I anaylise is that.teacher matters only if you really want to study.it is not like you want clear iit and narayana or other insitutes are the tickets to it.no one can make guide you unless you yourself guide you.according to me teachers were suitable to me.but some of my friends do not like the teacher.so see everyone has its own point of view.i really wanna give you a suggestion.do not waste your parents money.go to value for money not to brand only.just do not join these insitutes for cracking IIT.join only to gain knowledge.and do hard from today because tomorrow never comes. all the best for good future ahead