From Pew Research:
Rick Perry received the most favorable coverage of any candidate for president during the first five months of the race, but now Herman Cain is enjoying that distinction, according to a new survey which combines traditional research methods and computer algorithmic technology to code the level and tone of news coverage.
Perry lost the mantle of the candidate enjoying the most favorable treatment to Herman Cain two weeks ago, after the Florida straw poll in which Cain scored a surprise victory. Meanwhile, though he has often led in the polls, former Massachusetts governor Mitt Romney has received less coverage and less positive coverage than the shifting casts of frontrunners -- and that remains true even now. He ranks second in the amount of attention received, and the tone of that narrative has been unwaveringly mixed.
One man running for president has suffered the most unrelentingly negative treatment of all: Barack Obama