Positivism or Interpretation?

The ideas presented by both Hart and Dworkin are rather convincing and I'm having trouble seeing who I agree with more. I understand why Dworkin would assume that interpretation would be needed in the purpose of hard cases, but it seems likely that too much subjectivity is factored in by the judge. A judge could really phrase his interpretation in whatever he seemed fit, and say it convincingly by his expertise, in how it would apply to the principles that were established and chosen. Or how could one decide what principle would outweigh another? This seems to rely solely on subjectivity, unless perhaps it was ruled by a jury on which principle needed priority. At the same time Hart's notion of 'law is law' seems to lack authority to give an answer in hard cases, but maybe this is a necessary error in terms of the legal process in promoting the law towards better and more precise decisions and regulations. Dworkin's interpretation can backfire towards biased decisions while Hart's positivism can lead to a dead end. To me the hard part of deciding who has a better qualified idea of jurisprudence is going to have to be decided by the particular court case.