Usefulness of 1100 essential words of barrons

Hi dear friends.
I have spend some days on studying the vocabularies of “barrons 1100 essential words”. This book is usually recomended for GRE, but I am usingthis book for expanding the scope of my vocabulary. I think its vocabularies are not very useful in English. I feel I am kind of wasting my time on this book. Those who have read this book or English is your native language, can I know your opinion about this book? Is there any other book that is more beneficial for my purpose? (I have already read these books:504, barrons esential words for TOEFL and 400 must have words for TOEFL).