MDNA and then on a tier slightly higher, American Life. The rest of her albums are at least a 7.5 out of 10 with most of them being higher than an 8.5. Queen of critical acclaim.
For me MDNA is by far her worst album.
All the one who said it's Like a Virgin or Madonna are delusional. Even if whose album are not that good, at least they are her first works.
Meanwhile MDNA is a work made when she was 30 years in the business and it was a total mess. Impersonal as hell, generic as hell.