Hi Atreya, Welcome !
Hopefully someone else in the forum who has used Arif’s study guides can provide some feedback.
I personally found Wiley study guides to be very good for level 1. They are clear, concise and systematically work through a variety of examples to build your skills from scratch all the way up to the required standard for the exam.
Regardless of the provider you choose, always make sure you work all the CFA Institute end-of-chapter (EOC) questions, blue boxed examples, topic areas tests and mock exam.
As everyone knows, Level 1 is a massive volume game; so use a good study guide to learn the material effectively and test that understanding with the Institute’s question in addition to the prep provider’s ones. Also, pick a financial calculator and master its functions early.
All the best !