I think one of the reasons some people don't like dylan is because he seems to be a needy, perverted and inexperienced guy. On the other hand, many people prefer Sam just the opposite, because he is a more "measured" boy, calmer and has a little more experience dealing with womens.
But that's exactly why I think Dylan's character is well written. The contrast between the way of acting between him and his friend is due to this difference in experience of treating women.
I think people overestimate the negatives aspects of dylan. The character is very far from those typical porn game characters that are perversion made a person without any kind of moral.