Definitely, Katy.
Britney is like the definition of a puppet, so I don't think she's respected at all. Plus, she lip-syncs on a regular basis, and is constantly made fun of for that.
After the reunion with Chris Brown, Rihanna has lost most of the respect the public has for her. I know it's her personal life, but people can't be completely objective, and they will disdain her music for that as well