Paul,
i found studying for the PMP exam to be extremely difficult. My background is highly scientific (chemical process) and doing the PMP was like learning a second language for me. However, once I "cracked the code" for me (how the language works), studying became much easier.
I think the learning curve will be very subjective for each individual. Some will have a knack for it, others not. I did not and that made it difficult.
Your mileage will certainly vary.
Good luck!
