Corporate tax rate in Puerto Rico is 7%. You're not subject to federal taxes but you're still in the US. This sounds awesome.
Why should you move your business to Puerto Rico?
It is. I was CEO of a company with its primary hub in Mayaguez. Talented software engineers, fiercely loyal people. In those days it was a barrier - not insurmountable - to VC investment, but should be much easier now. Moving your business there, unless you are prepared for the distance and needing to be bilingual, not to mention the enormous debt ($108 K per household in a $20k average HH income economy) and unfunded pension liability the island has causing its future to be very rocky, sounds easier than it would be. You may be better locating yourself there and building the company locally. Some wicked smart people with bulletproof education either there or looking to go back.
If you look at the way taxes are structured around the company, the differences tend to benefit only specific circumstances. Overall you can have a low business tax rate, but then it's typically offset by a high income tax, sales tax, or property tax. The cost of standard wages or freight also factor into total costs in whatever location. Now, you don't necessarily have to be physically located in a specific state to be incorporated there. And I'm not an attorney so I can't provide legal advice. But looking at the corporate tax rate in isolation is a huge mistake. Total costs include dozens of factors that must be aggregated with tax rates to understand the effect.