Mariah Carey vs.
Madonna
Emotions vs. Like a Virgin
Music Box vs.
True Blue
Merry Christmas vs.
Like a Prayer
Daydream vs. I'm Breathless
Butterfly vs.
Erotica 
Rainbow vs.
Bedtime Stories
Glitter vs.
Ray of Light
Charmbracelet vs.
Music
The Emancipation of Mimi vs. American Life
E=MC2 vs.
Confessions on a Dance Floor
Memoirs of an Imperfect Angel vs.
Hard Candy
Merry Christmas II You vs. MDNA
Me. I Am Mariah... The Elusive Chanteuse vs. Rebel Heart
Honestly, apart from a few perfect bops, Mariah's first 3 albums were a bit too un-personal and generic, but things really lifted off with the amazing Daydream and
Butterfly before taking a dive with Rainbow and Charmbracelet. I do think her albums since then (also incl Glittah) have been keeping a good consistency, especially with TEOM and MIAMTEC.
Madonna started off strong with self-titled, before releasing one of the biggest turds of ha career (LAV
). She really proved her talent with LAP - one of my all time fave albums - and Erotica is criminally underrated. BS was a boring mess apart from the singles and I don't really need to say much about Ray of God. The 2000s were a bit inconsistent but she served us COADF so whatever. The 2010s have been a mess, especially with MDNO, but Rebel Heart served some bops and visual glory.
I stan for both of them and both have produced some of the best pop albums ever but Madonna takes the discography win. Now let's compare their whistle notes
