I think "Popular" adds weight to recent comments. This seems to be a much worse way of achieving what "Best" shoots for.
This seems to be a much worse way of achieving what "Best" shoots for.
Not necessarily. Someone who has already seen the best comments and returns a while later to see what new but good comments have been posted may have a use for it.
Way back in October 2009 Reddit introduced their "Best" comment sorting system. We've just pulled those changes into Less Wrong. The changes affect only comments, not stories.
It's good. It should significantly improve the visibility of good comments posted later in the life of an article. You (yes you) should adopt it. It's the default for new users.
See http://blog.reddit.com/2009/10/reddits-new-comment-sorting-system.html for the details.