I have admitted several times on this MB that I enjoy both Britney and Christina, so what is one more time? 
FWIW, I think that Christina has a much better voice, but Britney is more attractive. Britney did a photo shoot in a magazine I was looking thought the other day (I don’t remember which mag) and she looked great. Her hair is shorter and she was made up to look very glamourous.
No, I won’t attend a concert by either one of them, and Christina sounded like an airhead when she co-hosted the top 40 with Rick Dees, but I do like their music and will buy their CDs. I love to sing (when no one can hear me) and their songs are very sing along-able.