I really dislike this poll. It takes two extremes without even considering the middle ground.
Onto my experience, YouTube comments are a bit of a mixed bag. Yes, you do have some annoying posters, especially in videos that have been viewed a lot. That said, videos can also spawn very interesting discussions and it is at those moments that you can find some really interesting and intelligent comments.
Basically, YouTube comments are not that different from any other widely popular way of communication. There will always be bad apples no matter what you do. It is just a matter of judging whether it is worth having comments in spite of them and I would say that it is.