The Puerto Rico tax is...weird. It goes up highly progressively on value (I think 40% over 40k), it seems to be different for importer/dealer vs. individual, etc., but the 2015 electric exemption is nice.
(But, in exchange via act 20+22: zero capital gains (LT/ST), zero tax on dividends, and consulting/services/export revenue are taxed at 0-4% -- all guaranteed through at least 2035. Seems to be becoming quite the hub for traders and cryptocurrency people, plus some saas/consultancy types, which becomes interesting to me for network effect reasons.)