I see the Christina fans are trying to make themselves feel better about Christina's flop. Selling 4k less than Xtina doesn't mean she flopped harder. 4k isn't that big a difference. They both flopped (almost) equally.
Anyway, Miley was making the transition from being a tv personality whose fanbase consisted of 3-13 year olds, to a more sexy and grown image. She isolated her core fanbase so I'm surprised she even sold anything if I am honest.
Christina had huge hype around her and has been in the business long enough to build up a fan base (something Miley hasn't managed to do, due to her fans mostly being fans of Hannah Montanna, instead of genuinely being Miley fans).
Christina should not be flopping this hard. She's only sold 297k in 2 weeks Worldwide and around 150k in 2 weeks in the US. For someone who has promoted a lot, has had enough time to build up a fanbase and had too much hype, those numbers are abominable.
So no, let's not compare Christina and Miley. That's not fair to Miley.
Really want to measure Christina's success? Compare her to Britney, Pink and Beyonce.
I dare you.