Cad - I would definitely go with the confuser - I have got the AFE question book but never used it (I have heard quite a few times that it has mistakes in it). If you study the material well enough, you should be able to test yourself with the confuser and use it as a brush-up for the real exam. Bear in mind that the exams have recently changed, so make sure you get an up to date version of everything.
Best of luck
