Who would be stronger competition for Obama? Romney or Palin?

So far Republicans have not come up with an interesting candidate who could also do the job. Guys like Herman Cain get attention because he is black. He is also a Gaffer who cannot pass the intelligence test. Plus I looked it up last night and McCain got 16% of his votes from former Hillary supporters who are not voting on policy issues and will stay home if there are 2 black candidates so they think they gain something but they do not.