It is sufficient depending on how solid your gen chem foundation is. For ex, I picked up the book and was lost come the second lecture (gen chem was years ago ) therefore i bought the BR books, read all the sections, then came back to EK and it was a breeze. BR definitely helped refreshen my memory and in some cases it totally taught me the section. I've had friends pick it up and it was a godsend for them, because they either completely aced the class and EK was a condensed review, or they took gen chem recently while it was relatively fresh in their mind. Hope that helped. However I would advise in getting more practice passages, since the amount of practice in the actual review book is minimal. This is another reason why BR is awesome, PLENTY of passages. I'd get both if you can.
