The difference is that Christina never once tried to play the "good girl" or "Role model" game, she just straight up let it be known she was not the one girls should model their lives after.

Britney on the other hand got caught in all of the lies she was living (smoking, drinking, slutting around, and jerking her sponsors around). All while she was playing the role of little miss sweet and innocent and proclaiming herself an innocent.

Besides that Christina has more talent in her little finger than Britney has in her whole body. Not saying I really like her music but that girl can sing like no other.