Like with the other books Brown works plot twists into this one. Where he succeeded in the other books however by keeping them to a minimum, he feels the need here to not only put in multiple twists but then twist those twists. It does get a little contrived and silly. If you can take the position that hey it is just a book and does not have to make perfect sense, then I think you can still enjoy it. If something like that would bug you then I think you should probably skip it. He does work a lot of geography, mythology, and science into this book, and I think those aspects are well-researched and presented without stretching them too much. There definitely needs to be some suspension of disbelief with the science part of it, but it is not so far outside the realm of possibility that it makes the story totally unbelievable. Although I think it gets closer to that line toward the end of the book when all is revealed.
I think if you really like Brown's other books, then you can also enjoy this one. While some of the plot points get contrived and silly (mainly the who is working for whom and which side people are on, character motivations, etc) toward the end, it did not take away from my overall experience. I did not feel like I wasted the time reading it. If you have been lukewarm on his other books, then this one may bug you.