Its pretty hard to say who would have a better shot against Jones.
Both Machida and Rampage have a very methodical style. Both have strong takedown defense and use their stand up to win/finish fights. However, its the manner in which they go about this task that is the difference maker for me.
Rampage uses a boxing sand up style in which he uses his footwork to get into his range against his opponent. He, however, takes an exceptional amount of damage to get into, and stay in, his most effective range. Rampage is a very durable fighter with a strong chin. But his fights against Griffin and Machida showed that it is completely possible to use his willingness to wander into the pocket against him with rangy attacks. The Jon Jones specialty.
Machida on the other hand uses the exact opposite approach. He uses kicks and in-and-out punches to wear down, and when the opportunity is presented, finish his opponent. He tends to almost always stay away from the pocket and instead stay just outside the edge of his opponents reach. Machida's weakness on the feet is his "fighting in a phone booth" aversion. Shogun #2 and Rampage showed that if you get in his teeth with punches he's less able to counter and instead looks to escape. This is not Jones style. He uses a rangy style of stand up and clinches usually only when looking for the throw or a Thai clinch.
Since Machida's style does not lend an advantage to Jones, Machida is a better prospect from a stylistic stand point.
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