@kris Upvotes and downvotes work and do the job, the problem is that they require a disciplined community and admins.
If the ratings do not affect the real ranking, users do not see the point in it, they get irritated and the service slowly but surely dies. It happened with digg, it's happening with its Polish clone, wykop.pl, and it's happened with several other counterparts.
Unfortunately, the natural course of things. The site becomes popular, money begins to appear, this affects the ranking through sponsored content and begins a slow decline.
upvote/downvote meets the needs you write about. If it works as it should. It is less important whether it will be an arrow, stars, hearts or any other object used to illustrate the functionality.
Though maybe thumbs up/down would be a better choice than arrows.
jdp23