I would prefer an upvote / downvote system similar to Reddit's.
A common problem on forums, comments sections and social media like Facebook is that irrelevant, obnoxious interventions or plain trolling is depressing participation, allowing a minority of proficient commenters to completely control or hijack conversation. Reddit is far from perfect, but the possibility of downvoting into oblivion irrelevant comments really help to keep a pertinent conversation going among the majority who have something valuable to share.