Asking me to rate a MJ album is similar to asking a parent to pick his/her favorite child. How? Don't you love all your children. Each child is special in his/her own way. Each one of MJ's album is special in it's own way. I love and own all seven albums Michael released with Epic (including BOTDF) I honestly can't pick a "most favorite" or a "least favorite".
IMO, I feel people are not fair to Invincible. People still want to hold onto the "Thriller-era" Michael or the "BAD-era" Michael. It's very similar to when Michael was a teenager, people want to keep him "Little Michael'. People want to hear the "classic Michael Jackson sound". People want dance track, up-tempo, etc... But, Invincible was heading to an opposite direction. Break of Dawn (muscially and lyrically) is something Michael has never done before. 2000 Watts surprised me in a pleasant way. I love how he sang in the lower registrar. Whatever Happens is hauntingly beautiful and is different than his previous materials. To me, Invincible is a mature album. Yes, it lacks the playfulness and catchiness of his previous albums. But, it definitely grew on me. And, I truly don't think it's inferior when compare to Michael's earlier works.
If Invincible was released by Timberlake or Usher or Chris Brown, the album would be hailed as a big break-through. Since, it's Michael Jackson. People expected more! Sometimes, I feel people's expectation was unrealistic. I actually find it annoying when people always compare his works to Thriller. To me, different time, different situation and different music. It's like apple and orange.
Bottom line - Michael Jackson never released a sub-par album, not even when he was a kid.