That's the question of the day. And the answer is "it depends".
If you are willing to live in Puerto Rico and can do business there, then the short answer is yes, go for it.
If you think you can escape capital gains taxes just by moving, the answer is a lot more complex.
Slash Your Taxes To Zero? Not Exactly
Robert Wood a tax contributor to Forbes addresses the above questions in Move To Puerto Rico, Slash Your Taxes To Zero? Not Exactly
Puerto Rico hopes to lure American mainlanders with an income tax of only 4%. Legally avoiding the 37% federal rate and the 13.3% California (or other state) rate sounds pretty good. What's more, there is no tax on dividends, and no capital gain tax in Puerto Rico.