I agree that this idea could have easily been appended to one of the existing threads, because several people have posted similar opinions. However, if you want to make a specific comparison between US and International Dollar accounts here are my observations.

International Dollar Card (IDC) is a good product, but I wouldn't want to use it as my primary American Express card.

IDC offers a separate version of Membership Rewards, with different bonuses and redemption partners. In particular IDC does not offer "double points for everyday spending". (This said, a "double points for all spending" promo has just ended, but I do not know if these occur on regular basis.)

International Dollar cards are arguably not subject to US consumer protection legislation, and one may not have the same ability to dispute charges, especially after paying the statement on which the charge appeared. The bills are due two weeks after the statement date.

IDC online account information uses an older Amex interface which allows the user to view account transactions and balances, but interaction requires calling or faxing customer service in the UK.

IDC accounts are not reported to US credit bureaus.

Ironically, IDC charges more (2.74%) to convert foreign currency charges to dollars than do the cards issued in the US (2%).

dennis