Check out this post from someone else here on allnurses who has used the Mometrix materials: HESI A2 Study Guide by Mometrix Media LLC - Nursing for Nurses Might help you decide. "I posted this earlier in the student section, but I think it would make more sense here. I took the HESI for the first time today. I was a little nervous since many others that I know failed their first time taking it. I scored a 95.33% overall!!! I am so excited that I can now relax and spend some time with my family and friends. In case, anyone is curious I used the blue and yellow book(I think it was mosby evolve), and the Mometrix (something like that) study guides. The Mometrix I got from a link on here, the other I got from our college bookstore. I studied for about 5 days. It certainly helped that I just had bio and chem last semester. I hope that this can help! : )"