Dear Aspirant,

It depends upon the exam you are preparing for. For example if you are preparing for exams at +2 level, then unacademy is good as it has good material on JEE, NEET, NDA, etc.

For preparing about exam at graduation level, Gradeup is good as it has some good community of graduates preparing for exams like PO, GATE, etc.

Hope this helps. Thank you.