H. c. verma is no doubt one of the best book for those students who are preparing for jee. although it is said that if you can complete h. c. verma you can crack jee. but with my experience this book can not be preferred for concept building as it is more focused on problems.
you can use this book as your reference book to solve good problems but you think you want to buy this book to enhance your concept then it will be a wrong decision.