Paul and Cruz used to be lumped together as "Tea Party Republicans" but in the last year or so Paul has done a good job of differentiating himself from Cruz, while at the same time not associating himself with the Bush/Romney/Christie GOP establishment wing.
Paul has always done well in polls, at least compared to his GOP counterparts. In spite of the press, the Cruz-Paul "Tea Party Republican" thing never really stuck. Paul has significant differences from Cruz, Cruz is right-wing at all costs, Paul has differences that would actually attract young people and people who don't usually vote Republican.