general

First Aid for Step 1 is like Netter's -- not very good and highly overrated. The book is a mess of random information that has no connection and no flow to it, and is therefore difficult, frustrating and low-yield. The only good part of the book are the images but these can be found online (WebPath) for free. I skimmed First Aid once, tossed it aside and spent all of my time with Step-Up which is a MUCH better book.

First Aid is essential for Step 1, and I found it very helpful for many 2nd year tests, but you are going to need MUCH more than just this. I took First Aid with me on the day of the test, and tried to look up any questions that had stumped me right after I completed a section. It is just not detailed enough! Step 1 demands that you know tiny details that are not covered in First Aid. Overall, it will cover the big picture, and it's not a waste of time, just don't be surprised when you find extremely detailed questions on Step 1 that you can't answer with First Aid.

If you plan on taking the USMLE Step 1, forget about trying to read all of those high yield books... there just isn't time. Instead, study this book, and hit up the Kaplan Qbank and you should be in good shape if you've been paying attention in classes for the past two years. It's got very concise and specific info that's great for answering standardized test style questions. It's absolutely essential, and worth the investment. Also, if you have an older version.. keep it. They dont change much year to year, but for sure grab one of them because it will save you a lot of time, and can only help your score.