You are lucky too, Matty Jam and myself are prolific posters over on the Prince.org as well, so Prince is a big part of our lives. In his case MJ is his #1 artist, and my #2 artist behind Prince. I pretty much live and breathe Prince, but Michael Jackson is never far from my thoughts. No one can compete with a genius like Michael
.
Don't get me wrong, Michael is awesome too and as my #2, he is a lot closer to Prince than he is to my #3 artist - Madonna. I agree with Matty Jam about quality control, Michael's albums were not just good, they were perfect, OTW to Dangerous do not see a single mistep, the meticulous quality of every song, there is no filler and no slack, every beat had to sound funky and be just right. Commercially perfect and great product. History nearly reaches the mark, and BODF and Invincible are great too, but Michael's quality had slipped a bit. There are still highlights like Break of Dawn, TDCAU, Ghosts and the like that would fit into the tight quality control of Bad and Thriller, but songs like The Lost Children and Privacy would be locked out!
.
I have liked Michael longer, but I guess Prince is #1 for me, because I am not as big a fan of commercial perfection as I am of free form and fun. Michael's songs were rigorously structured, what you got on stage was the album track with some incredible dancing and acrobatics, with Prince however the stage and his bootleg mixes of thge songs were so different to the album versions. That is what does it for me, the fact Prince always mixed it up and in reality, Prince could never make an album as tight and rigid in its quality as Bad, but his ideal album would be fun and a mix of styles. Great as Bad is, its all basically tight dance pop grooves, a bit of balladry and decent rock cuts. Sign o the Times on the other hand has Jazz, Funk, Pop, Soul, R and B, Sexy ballads, smoochy ballads, gospel, live stage soloing and devotional ballads along with gender bending funk and hippy songwriter stuff. Seriously that album is everywhere. Likeme, I am everywhere I like variety and spice and as much as I love Michael and the Bad album, it just lacks the adventure and experimentation of Prince. Of course not every experoiment and gimmick of Prince's worked. His albums would have a 1 to 10/10 songs on most of them, with mostly 10s, but 2s as well, whereas Michael every song was a straight 9/10 if you get what I mean.
I agree with Matty, that Prince never gave his music enough time to bed in and he lost interest in a project too quickly. Prince got frustrated with the time it tool a project to come out, most of 1987's Sign o the Times was written in late 1985 and mid 1986, by mid 1987 he had the Black album in the can and was already working on some cuts that would end up on 1990's Graffiti Bridge. Meanwhile Michael would milk a project so at least 7 singles over 2 years would come of it and do tours and videos along with publicity so albums stayed on the charts and high on the charts for ages. Even in the 80s, the typical Prince project came out, peaked and dropped off the chart within 20 weeks (Purple Rain and 1999 being the exceptions), whereas Thriller and Bad spent about 2 years in the chart. Thriller spent 37 weeks at #1 in the USA, yet another 50 or more in the Top 10 and over 100 weeks in the Top 40, even Purple Rain which spent 24 weeks at #1, spent only 37 weeks in total in the Top 40 and 58 in the Top 100 (In its initial run, the album came back in 2004 and 2016 after his death).
Seriously though, there's a lot that sound similar production wise on the Prince albums -obviously theres many albums from that time that sound the same. Sometimes I feel if Prince had released less, a lot of his albums would have been better. Although I do love Lovesexy and the Black Album, even Batman has some good stuff. But MJ's albums are mixed and mastered to perfection and every track is worthy. Very different artists in that sense of course. 
