The thing is, in many ways Best is actually a better player. His flick ons are vastly more accurate, he has a much better touch and shows some good pieces of skill on the occasion.
However Carroll is such a monster that if a team is built around him then he will always score more goals. I thought liverpool were trying to do that with signings who can book a really good ball in the box such as Downing and Adam but they don't seem to want to make use of him properly at all.
edit: oh and my answer is Best.