I think Millz won. Mook even kinda admits this, he says he was a relative nobody & wasn't even supposed to be able to hang with Millz. Millz had a deal, really you could argue he had no business battling anymore but he gave Mook a shot. Dude was just too polished and totally swagged on Mook. You can tell Mook was just raw, and eager to get his shyt off. It's insane how much more comfortable Mook looked vs Lux, it's like night and day. I think the first 3 rounds were debatable, if it ended there you could give Mook the W. But once Mook ran outta personals, Millz pulled away. From his first line to his last line, he made me feel like Mook was beneath him. Mook had some nice personals, but none of them seemed to affect Millz at all.
Mook came straight at Millz jugular with personalized material, which began the transition of written battle rap from "Watch me captivate the crowd because I'm hands down nicer than you" to "I'm going to change how everyone looks at you from now on" (character assassination). So when Millz left the game, Mook became the standard bearer, even though he lost. If Millz stayed active, who knows what direction battle rap would have gone in.
I love that the battle is only 20 minutes, not too long, not too short. You can rewatch it on a whim.