Personally I could happily live with vs. threads if everyone were mature enough and could write out detailed arguments with valid points and generally not act as though whatever opinion they hold is right just because they hold it. Understandably the last bit can be hard to achieve because if you hold an opinion there's usually - though not always - a reason for it, so it can be a bit of a challenge to accept that sometimes the belief you hold is not actually correct and more often than not people out right refuse to admit defeat and start flaming and making personal remarks. In theory vs. threads can work well and bring about intelligent discussion it's just that very few people are willing to have their opinions changed. However, the subject/s used in vs. threads plays a part. "Whose a better character X or character Y" is asking for low content especially when the thread is joined by those just wanting to post simply because they can and not because they have both knowledge and interest on the subject. But, and I'm not joking here, fayboys aside, it is more than possible (at least in theory) to have a thread discussing which is better, the Xbox 360 or the PS3 because they both have aspects that could be conceived as better or worse and given the right poeple you could come up with a pretty good verdict. Unfortunately one of the major draw backs of vs. threads, even if you had a whole forum of reasonable debaters and could actually make it through a topic without acting like complete muppets is that there's the repeat... repeat... repeat... repeat... factor. Because assuming it isn't a complete one-off in all aspects there is going to be someone somewhere down the line who will ask the same question and then we get the whole necromancy against repeating a topic conundrum.
The pity for me is that nowadays, more often than not, even The Escapist - once a bastion of civility on the web - has, just through growing popularity and therefore numbers, succumbed to the level where a most of the users cannot maintain a level of decency and open-mindedness to allow a vs. topic to work. All too many are just looking to boost their post count by replying to a topic with embarrassingly short and badly thought out answers. Even if a reply to a thread is wrong - at least in your view - if it's lengthy, well written and, if necessary, backed up with links then there's a chance that you'll understand their view better. And even if you don't end up with a changed opinion there's nothing wrong with both parties agreeing to disagree; it just doesn't ever seem to happen.