Britney BY FAR.
Beyoncé's "receipts" for her supposed influence are all generic compliments

Generic compliments =/= influence
Beyone herself has copied Britney a few times. Slave routine, MATM AMA '03 costume, PR in early 00s, and many more.
Britney isn't influenced by Beyoncé one bit. She's nice and gave a generic compliment just like everyone else Beyoncé "influenced" does. Beyoncé has not influenced one pop girl as much as Britney influenced teen stars.
Actions speak louder than words!
EDIT: Does anyone find it interesting that Rihanna's first two eras (her least successful ones) she was inspired by Bey more than her other eras, when she ditched her and picked up a
Britney reject as a song she became a superstar.