When it comes to cracking exams like AIIMS you should always go for the one which is the most experienced in their fields. This only points out to the one which is the oldest and still holds the number one position in the field of PG medical coaching. According to my personal experience, I would only suggest bhatia for your preparation. This coaching institute has always been the best in preparing their students for the medical exams, from past so many years.
Faculties here the most renounced and experienced a lot. This allows me to think they must a great doctor in the OT and a perfect teacher on board.
I have always loved their notes which is very crisp and easy to understand and grasp.