While Indian institute of Science is a renowned place for higher education, the way of studying itself cannot be said as the best. I say this because there are many other institutions around the globe way better than this one that can give you a better experience.

I would recommend you to do PhD abroad where you do not have to simply pay fees and not get served for what you have spent. There are many institutions abroad that give you exactly or more than what you have paid for. Doing PhD is no joke and it is not easy as doing your bachelors or master for that matter. You need to have steady flow of funds for your research, paperwork, seminars and other preparations.