A group of friends and I were in the bookstore the other day wondering what book would be a good replacement for First Aid (since like you said, it is not as good for Step 2). I had already bought Crashing the Boards, then a Peds resident said to get "Advanced Life Support for USMLE Step 2"....She said that when she did questions in the books and got them wrong, this book had it all, and recommended it as the subsitute for First Aid for Step 2, although she also used that too...She totally sold me and I bought it. I havent started studing yet, but I have heard really good things.
Hope this helps
Peg