I would suggest that both appear here. Personally I would prefer votes to be on quality of post rather than popularity of position as that leads to the possibility of examining an issue from multiple viewpoints.
(When responding to a post that has been thought out, but down voted, I feel the need to point out that although I disagree, I'm not the one downvoting.)
I do think that voting improves the quality overall. But a better system might be separate options for 'agree/disagree' vs 'quality / pithy' posts. (I also thinkbthis would be horrible UI, so meh)