They have absolutely nothing in common...
One can sing, the other can't.
One can dance, the other can't.
They are musically different. So what...they're about the same age and came out at the same time, but it's quite obvious both have grown in different directions.
And yes, since this is my blog, I will call out people...Mazen, Cesar, Cool Breeze (Moon Shine aka Boom Boom aka Ancient Ruins
), malvatar. Seriously, shut up. Shut up. No one cares about record sales anymore. CD's don't sell ****. If you think Britney is going to go 7x platinum, you're wrong. Don't even bring up single performance. Christina may have disappointed recently, but Britney just gets stomped on, spit on, and wiped with. There really is no argument here since neither can pull off a top 10 single as of late. The haters just love who they're hating on, or else you wouldn't constantly hate on them. Mazen, Cesar, Cool Breeze, XTIAN...you're beautiful, words will never bring you down.
And malvatar, well you're just sad, sadder than half of Britney's single performances on the Hot 100.