Myself, I studied from American books because I'm USMLE-certified, so I knew where to look. For me, that was not the issue, but if you come from eastern Europe, as I do, where we didn't have one single written exam, you are seeing multiple-choice questions for the first time in your life. It takes some time to get used to that. That's why I was talking about bridging programs during the course of my conversation. I passed with 90%, but there are people who pass it with 100%. That does not mean anything.
In order to safely practise medicine, and I'm sure even Dr. Bowmer would agree, even 60% on the evaluation exam is enough. People are coming here with an evaluation exam taken in their home country, at any time and at any number of attempts with any school, and they pick and choose their specialty. This is the crux of the matter.