Romney will do well in polls until the real electioning begins. His Mormon faith will become an albatross around his neck. Mormonism has so many quirky beliefs and tenets that people will hesitate to vote for him because of fears where his beliefs will lead him.
*** Mitt has the same problem McCain had, he is a RINO. As such he can't be elected in a general election. Most Republicans won't vote for him.
Real Clear Politics is a partisan site, so their polls can't be trusted.