Step II Kaplan Step 2 CS or First Aid CS?

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I used FA initially and then went to Kaplan Step 2CS (which I liked better because it explained the little logistics). Best thing to do is to go to the bookstore and take a look at both books to see which one fits your learning style.
 
I used FA and did fine. But I can't compare it to Kaplan since I didn't use it. You should take a look at both before you buy and decide yourself.