Eh. No, it's not the best, it's not anywhere near the best, but he gets an unfair amount of slack for it. He's good on the inside because he can use his uppercuts and hooks to maximum effect, and he's good on the outside because although he has a poor jab, he can use his oblique kicks and various other tools to set up shots.
What he's not good at is fighting in middle range. His hooks and uppercuts aren't nearly as effective there, and he can't really throw his kicks with confidence. As I mentioned before, his jab is poor, and I believe that's what you need most to fight at that range in MMA.
Is Reyes better at that range? Probably. Is he going to be able to keep the fight there for a long enough time to make a difference in the fight? Maybe, but I wouldn't bet on it.