Staightfoward to the points (from my perspective):

• My preparation material:
  • PMBOK: Although offical guide for PMP,  I do think it's too abtract, textbookish, and boring (all about definition and concepts).
  • Rita PREP: Strongly recommended. The NO. 1 useful material. Worthy to read thoroughly at least 2 times. 
  • Headfirst: A very good entry level book with a bunch of practical examples shown to easily understand PMI ways of managing a project. 
• PMP real test:
  • Difficult level: Between the Headfirst 200 practice and Rita PREP practice (not the FAST track). I already knew I would pass the exam after I finished the first 20 questions or so. 
  • Take advantage of the 15 mins tutorial time befor the test: you may write down EVM formulas and management processes. 
  • A lot of situational questions especially those asking what's the next step: Most of them about the PMI way to deal with changes (change request).
  • Like normal distribution,  real test has a little portion of lenthy wordy questions (not necessarily dificcult) and damn easy one-sentence questions respectively.
  • Only a few ethical questions (four ethical principles: Responsibility; Respect; Fairness; Honesty).
  • Risk, quality and procurement are the three domains mostly tested.
  • No need to memorize ITTO AT ALL: Only two or three questions directly asked about ITTO (using eliminaiton to pick up the right answer). But we do need to understand PMI methodology towards project management by frequently reviewing ITTO.
  • Sitting there for 4 hours is little bit challenging. DO take a couple of breaks in the middle of the test to get yourself refreshed (Remember the clocking is still going). 
• Suggestions:
  • No need to buy those paid tests: totally a waste of mony and time. I only did the practices from Headfirst and Rita PREP, plus a couple of free simulated tests.
  • Oliver 75 sample questions: I know a lot of people recommend that, but it's really way more difficult than the real test. I did Oliver 75 scoring around 65% on my fist only try and I feel like a great portion of those questions are out of PMBOK scope. 
  • DO NOT overstudy (reading a variety of books and doing a number of simulated tests is not advisable).
  • Spend a great deal of time anzlyzing the questions you answered wrong to bridge your knowledge gap. 
  • Again, understanding PMI way of project management is the key to pass the exam. Rivewing the Rita process as much as you can.