Earlier quoted context omitted.
US Citizenship is essentially an IRS trap. She'll be forced to pay taxes on her worldwide income for life, regardless of where she lives. I'd think twice. She can have all the benefits with just a green card for next 7-8 yrs.
Citizenship has nothing to do with it. You are still taxed on worldwide income if you are a permanent resident or in many cases even if you are here on a work visa.
Not so fast if she's citizen. Think twice.