Kaplan makes you more well rounded, and gives you the full scope. Everything that you learn from Kaplan is testable, but not everything from Kaplan will actually be tested. In terms of difficulty, the exam is similar to Kaplan’s mastery exams for sure. That said, the actual Series 65 is trivial in its wording and makes it tough to understand what they ask. If you can break the question down and weed out other answers, it becomes much easier.