Don't know if someone commented on this before but it's actually really good, when she sings low and slowly, especially compared to the rest of the song. I hope Back To Basics has a lot of songs like it.
Even my mom said it's a shame that she screams the entire song and only after it shows that she can sing.
I think the video really showcased her versatility. It was brilliant. It shows she can belt high-energy hits and slow it down and really engage into a bluesy song.