As far as lyricism, Lux by a mile. Let's be honest, nobody is quoting anything Black Thought said, not because it wasn't good, it's ust because the individual lines in of themselves won't match up bar for bar. They read better as a collective. Where as Lux was a display on high-level wordplay, similies, punchlines, metaphors.
HOWEVER, Black Thought's was a better display of full rap skill in terms of cadence, breath control, staying in pocket, delivery.
I voted Lux because I enjoyed it more, like
@cornercommission2k12, as battle rap fan, I'm more heavily into metaphors that's why the Ras Kass, early Jay, Joe Budden rank really high to me in terms of lyricism. I've watched Lux's freestyle over 20 times. I watched BT's twice.
But if I wanted to show someone why rap is the best genre and why the skills it takes to be a great rapper is greater than any other artform, I'd show them Black Thought's freestyle.