OTW has definitely aged the best for its age. That album is 29 years old and some of those tracks (Rock With You, OTW) could still be releaesed today as new while others such as DSTYGE sound very disco era, but still sound good.
Bad has aged the most. I enjoy the album, but whenever I listen to it, the overuse of the drum machines and synths make it sound very 1986-87. The album was even a bit dated when it came out. 1987-88 was the beginning of the New Jack Swing era and since I'm sure MJ had been working on Bad material since about 1985-86, the album really sounded dated by 1988 standards (think Bobby Brown-My Prerogative, etc.). MJ did hop on the New Jack Swing by 1991, but I think that the Dangerous album had enough variety of styles among the 14 tracks that it managed to not get too caught up in that specific era.