This is my 2c.
LOSS (small or none)
- your country citizenship? (In many cases you can preserve dual citizenship – US does not force you to give up your old citizenship, but some other countries like India, Germany etc.)
- your right to vote at your country? (Generally, for majority of countries this is preserved)
- your right to become a politician in your country? (This is limited by the State Department policy, but generally I do not think that many ppl very forbidden to take role in politics. I think that State Department is worried only if you want to do politics in terrorist, unfriendly to US countries etc.)
- you have to pay U.S. taxes on your world-wide income (to be honest – I do not see this as a huge downside…..if you have GC, you are in the same situation)
- have to serve military if required (not a big deal since U.S. has almost exclusively voluntary army)
GAIN (only plys)
- right to vote in the US (and run for the office)
- can leave US for more than 6 months
- can apply citizenship for your kids/parents from another country
- Green Card can be taken away very easy. It takes lot of sweat for a citizenship to be revoked.
- As a citizen, you do not have to deal with USCIS all the time: report change of the address, answer inquiries, extend your GC etc.
- In case of emergency in foreign country, as a US citizen, you will be evacuated by the Embassy.
- you will not need visas for many countries
- you do not have to carry GC all the time with you
- morally – feeling as an American is great thing…there is no more open, welcoming and opportunity offering country than this one.