In reality, I should find Hayden easier to sympathize with because I'm also a sentimental and negative person but Brett's character is really comforting. A character who understands himself, knows how to calculate and balance everything to get what he wants is truly very comfortable. I don't know why I think Hayden's feelings are more complicated and confusing than Brett's, but I guess everyone has their own opinion.
I think you have a great point, because what we see from Hayden is feelings, but from Brett... we really just see motive. It's more calculating and identifiable which makes it easier to digest than trying to untangle the emotions that Hayden is shown processing. It would be very interesting to see the narration shift and see the emotional, more inward side of Brett.
i don't think i've ever understood a character as much as i do brett. the way he thinks and the manner in which he acts feels so comparable to my life (minus the extremely intense sex, darn it).