Extremely tough. It's so hard, but in the end...
Till The World Ends vs.
S&M Tie
Hold It Against Me vs. What's My Name
Inside Out vs. Cheers
I Wanna Go vs.
Fading Tie
How I Roll vs.
Only Girl In The World
Drop Dead Beautiful vs.
California King Bed
Seal It With A Kiss vs.
Man Down
Big Fat Bass vs. Raining Men
Trouble For Me vs.
Complicated
Trip To Your Heart vs.
Skin
Gasoline vs. Love The Way You Lie Part II
Criminal vs. Who's The Chick
So as you can see, it's all tied up
. In the end I'd give the slight edge to Rihanna because compared to her last albums, this is her best. Compare Britney's Femme Fatale to her other albums, it's near the bottom