Swedish pension/How is it taxed in US if you choose to be taxed there.

I am thinking about moving to the U.S. on a on and off basis, retired, with Swedish pension, will soon have a green card. My questions are:

- Is there a benefit to choose to be taxed in the U.S. instead of Sweden ? (apprx. $63,000/year)

I know you have the choice if you live in the U.S. for more than 6 months and choose to 'write yourself out of SWedish IRS).

Any references/links that may help me out?

Thanks