The one thing you have to remember is that the test is based on the PMI, not what you may have experienced in your career. Most PMP prep courses get the job done once you submit to the idea that you are regurgitating what PMI wants. There are a number that teach strategies like memorizing all the formulas then writing them down immediately when you sit down (I highly recommend that). I took a boot camp course from Cheetah Learning, and when I sat down to take the test, I just blew through it and hit the submit button with 100% confidence and passed with no deficiencies. I have a love/hate relationship with PMI. I was the evaluator for PDU credits for a university for a while. I do think the process made me aware of a lot more aspects of PM that I would have been exposed to otherwise. The PDU requirement does challenge you to keep current, and PMI has actually made that easier. That said, there are a lot of PMPs running around who are terrible PMs and we just got rid of one of them last Winter.