i found it interesting when they discussed this on NFLN last night. They were implying that one of the reasons why teams tend to lean towards them is because owners/Gm/coaches are very careful about who they give their money to. If they decide to give the high character players a bulkload of cash, they won't be busting out all over the place once they have it.
While high character guys tend to play better once they get their cash, low character players could start blowing their career by doing stupid things with that cash and not play as well when they recieve their money because they already have it.