– You will reduce your tax burden drastically – You will significantly reduce your tax filing burden. – You will be done with the US tax system for good. – You won't have to juggle between different taxation systems. – You won't have to take all your assets out of the US (note that you'd have to pay taxes on your US assets).
– You will no longer have access to the US job market. – You'll have a much harder time getting into the US unless you're a citizen of a Visa Waiver Program country. – You won't be able to vote in the US elections. – You won't be able to access US consular protection in case of an accident in a foreign country.