Well I think both of them have lasted long in the industry,
Right now both of them have certain weak aspects, Beyonce lost her hit maker reputation with her last album, while Britney lost her album selling power with her last album.
Beyonce is more critically acclaimed as an artist, while Britney has more cultural impact in pop music as an artist.
Beyonce proved that after more than a decade she could make her album platinum while Britney proved that after more than a decade she could have hits and top 10 singles.
