Well it's no use comparing Mariah and Madonna (it should be between Mariah and Mary J. Blige or Madonna vs Britney Spears, for example).
Btw Madonna always surpasses Mariah (and any other artists) in the first few weeks sales, but eventually she will lose closely. It's becoz Madonna is more popular worldwide but if she just churns out piece of crap then there's absolutely no hope for high sales.
I bought both albums and personally I think Mariah's is better (although 4 Minutes is on par with Touch My Body). Sry Maddie, try again nxt time