I thought the NCEES practice exam is the best "representation" of the exam. I don't know about everyone else, and I'm unsure if I'll pass, but a large portion of how well I will do on the exam is because I have a lot of experience in the field in this industry. Without it, I would have to believe most people would do poorly. The exam is difficult and rightfully so that it hopefully removes incompetent people from passing; or giving you a practice exam that would be so close to the exam everyone would pass.
When i failed in April, I walked out feeling like a no/maybe on passing. And it wasn't by much. So i studied my butt off for 3 months and now in the (i'm hoping) yes/maybe. That's what they are looking for.
My only complaint with the exam is I feel like there are a large number of questions that don't properly evaluate your understanding on the principles. Some books, especially Wildi, in my opinion have great practice examples that are fairly simple and really show your understanding of the principles and how things work. Some on the exam are so blatantly way out there that it is irritating. But, I guess they need some hard ones and some curve balls