Puerto Rico has a population of 3,800,000. Puerto Rico has had 67 champions.
Mexico has a population of 116,000,000. Mexico has had 194 champions.
So Puerto Rico produces an unbelievable amount of champions per capita over Mexico who falls about halfway on the list with champions per capita.
Putting it simpler if Mexico had Puerto Ricos population they'd have around roughly 6 champions. And if Puerto Rico had Mexicos population they'd have around roughly 2,011 champions.
Having 116 million inhabitants and your greatest rival is an island with 3% of your total population is embarrassing. Not only your greatest rival but arguably may have more wins over Mexico than Mexico over PR.
I say Puerto Rico is the better of the two. Regardless of all this, neither produces the best champions, the US is without a doubt the one that produces the best champions. Rarely skilled, style wise unique and seem to be distinctively gifted. Just the ATG... Ali, RJJ, SRR, SRL, FMM etc..