Jones. Has never been in trouble in his career, or shown any signs of weakness that could be exploited, other than getting briefly caught in an armbar by Belfort. He is also a savage finisher, finishing 10 out of his last 11 fights (I consider the Hamill fight a Jones stoppage) in brutal fashion. He's beaten some seriously talented fighters, and done it in the most impressive way, by finishing them. I love GSP, but Jon Jones is the best fighter on the planet right now.