Rihanna by far. Probably the easiest poll I've ever voted in.
Just because Katy's commercial doesn't mean she's manufactured. She clearly has a lot of input in how the Katy Perry brand is used.
If she's manufactured, it's been done by Katy Hudson, not by some suits in Capitol, unlike the other option.
And just because Rihanna has "Experimented" with different sounds doesn't mean she wasn't told/made to to experiment with those sounds.
and her most recent new song reveals how manufactured Rated R truly was, so don't even try to use that album as an example of her being non-manufactured.