For the General Public? Obviously Beyoncé. The general public isn't exactly aware of everything that goes in Pop Culture. They are so ridiculously blind for Beyoncé eventhough she is nothing out of this world. It's just because she is a great singer and a nice dancer that they think she's God.
Personally, I find Britney Spears' choreographies way more complex and harder than Beyoncé's. You don't need to quote me Britney's weaker choreographies. Instead, you can quote me with a better choreography (and a better execution overall) than "Slave", "Toxic", "MATM", "Boys", "Overprotected"... Hell! Even "Hold it Against Me" of Beyoncé.
I can see an argument for Britney out-dancing Beyoncé at her peak, but even if that's so, the GP certainly does not consider her that girl anymore, so it's clearly Beyoncé.
They marketed Britney as some great dancer/performer during her peak, and almost all her music videos have dance choreo, so I think people are more familiar with Britney as a dancer.