Yeah you should start with XXX, it's easily his best work. Just to forewarn you, his style takes some getting used to. He raps in a really high-pitched voice most of the time and the first couple times I heard him I thought he was pure garbage (the first time I heard him my buddy showed me "Monopoly" and I told him to turn it off after about 20 seconds.) After I got used to his voice though, I quickly became a big fan of his.
4/5 Protest the Hero/Battlecross
4/9 Danny Brown