Hi Sukesh,

In order to prepare for JEE along with your 12th boards, in my opinion Byjus is a much better option, because byjus has a unique way of making you understand concepts in a much better way. It teaches you topics with real life examples which helps you understand as well as remember things in a much better way. They also have quizzes as well. 

But if are a dropper and want to prepare for JEE, I would suggest you to follow Byjus as well as take up online test series from Kota, easily available online. Test series will help you to get thorough with the JEE examm pattern as well as you will get to know time management as well. The above can be followed by the freshers as well, if you can handle so much pressure at this time.

Hopefully this helps.