Although they were different centuries I'd still easily compare the two...
Girls Aloud are the best and always will be! They have an amazing flaw-free discography!! Just perfect pop!
"Sound Of The Underground", "No Good Advice", "Life Got Cold" and "The Show" are of far better quality compared to the likes of the childish "Wannabe", "Say You'll Be There", "Stop!" etc but like I said...different centuries!
I mean GA discography is so diverse as well... From "Swinging London Town" to "Black Jacks" to "Love Is The Key"
Girls Aloud. The Spice Girls' best tracks are their biggest hits. In addition to amazing hits, some of the best GA tracks are non-singles, or even B-sides.
Usher vs Justified
My Way vs FutureSex/LoveSounds
8701 vs The 20/20 Experience
Already done
Madonna vs. Janet
J.Lo vs Rihanna David Bowie vs Prince Lady Gaga vs Lana Del Rey Kelly Clarkson vs Carrie Underwood
Adele vs Amy Winehouse
Bruno Mars vs Justin Timberlake Jay-Z vs Nas P!nk vs Avril Lavigne Beyonce vs Christina Aguilera
Britney Spears vs Shakira Demi Lovato vs Selena Gomez & the Scene Hilary Duff vs Miley Cyrus Florence & the Machine vs Marina + the Diamonds Lil' Kim vs Da Brat
Destiny's Child vs TLC Eminem vs Kanye West
Ke$ha vs Katy Perry Mariah Carey vs Whitney Houston Mary J. Blige vs Toni Braxton Taylor Swift vs Carrie Underwood Shakira vs Jennifer Lopez
Kylie Minogue vs Madonna
Beyonce vs Britney Spears
Nicki Minaj vs Lil' Kim
Lauryn Hill vs Missy Elliott
Ciara vs Rihanna Miley Cyrus vs Selena Gomez & the Scene
Demi Lovato vs Taylor Swift
Keri Hilson vs Ashanti
Christina Aguilera vs P!nk Girls Aloud vs Spice Girls