I purchased another study program last year, spent $900 and didn't pass! Not blaming them entirely, as it may work for some people. I did all of the practice tests, and repeatedly got high scores, so I thought I was ready for the exam (this was the old standard exam). The actual test was not what I had practiced. I found TDC to be clear, right on, and easy! The tapes explaining the rationales were SO helpful! I went into the exam feeling confident and passed. I can't thank TDC enough! Now on to the Clinical!