Gonna go against the crowd and say there's actually quite a few official MJ remixes that I enjoy. I actually enjoy many of the remixes on BOTDF and I often find myself playing them when I'm casually doing something. They're pretty cool to play quietly in the background when you're online early in the morning.
Whether or not they do justice to the song... I think a couple do. The remixes for Money, Earth Song, You Are Not Alone and
maybe... HIStory do some justice for the songs I feel. I'm not expecting any of the remixes to reach the level of the original song and honestly as long as the remix sounds good (as in, I like the instrumental and how they've played with Michael's vocals), I'm satisfied.
I do find myself enjoying unofficial fan-made remixes more though. I actually typed out a whole bunch with links to them before seeing this thread was for official remixes
EDIT: Oh yeah, if you count the contemporisations on Xscape, then I looooove LNFSG, Loving You, APWNN, STTR and Xscape. The respective producers did an excellent job on those tracks (and honestly, I play them more than Michael's demos. No disrespect to Michael obviously, it's merely a subjective thing)