Rappers who spit fast sound tight at first, but sometimes they are too fast. I personally enjoy hearing a rapper tongue-twist every now and then, but I'm more into complex rhymes.. I've noticed that fast rappers tend to slow down a bit as their lyrical ability matures and their rhymes become nicer. When you spit shit out too fast, most people don't catch half the shit you're saying. When your shit becomes more polished, you want people to understand and hear everything you're saying.
Twista is an example.. At first he spit shit fast as fuck and it was hard to understand what he was saying. Not that it really mattered because he didn't have much content anyway. But he slowed his style down dramatically when he dropped "Da Resurrection" and his lyrics were 50x's better. He eventually found middle ground when he dropped "Adrenaline Rush," with a quicker flow but not so quick that you can't understand what he's saying.
Anyway, that eNe dude is quick as fuck and he sounds nice, but sometimes you can't understand anything he's saying unless you look at his song lyrics.