I recently passed by final PRM exam (#3) and can say that the RiskPrep materials are much more helpful than Kesdee. That said, the Kesdee cost is minimal and covers somewhat different material.
In truth, both sets of questions were a good prep taken together but nothing like the exam which was a lot trickier i.e. you have to know the concepts and meaning vs answers to questions. The Handbook is chock full of mind-numbing formulae and headache inducing text. A really good way to study is skim the Handbook, do the questions then go back to the material and understand the concepts. Pay close attention to the additional papers re: Basel II, SCAP, Stress Tests, etc. More questions than one would have thought on those. There wasn’t much in the way of quant calcs which disappointed me but I managed to pass anyway. Your questions might be more quantitative. Depends on the set from which they select.
Good luck.