I am legitimately intrigued by this analysis. I've always wondered why I found certain rap so much better than others. I stopped liking the kind of rap that was becoming popular around the time of Snoop Dogg, Dr. Dre, Tupac, etc. Looking at this data, it pretty obvious to me that the stuff on the right I tend to like a lot more than the stuff on the left. Sure enough, I just listened to Aesop Rock for the first time and it is exactly the kind of rap I enjoy.