A little difficult to keep straight at first, the time difference between the parallels kept throwing me off but I see how it was a necessary plot device to keep the MC in the dark. I could have done without the "old, wise" character throwing religion into the pot (yeah, guy, if you're going to seriously try to work out an equation for "fate" re: the path your divine creator intended then of course you are going to be laughed out of the scientific community).
I know the point of the book wasn't about the science, but there was a real opportunity to explore the actual concepts of predestination and the illusion of free will but instead we got a feel good line about destiny and paths and blah, blah, blah.
I had no huge issues with the MC but I still feel I would have been much more engaged if the genius friend had been the protagonist instead.