It depends whether the US has a tax treaty with your country of residence.
If there is a tax treaty in place, then you will avoid double taxation and the company will be taxed where it has a permanent establishment (i.e. the place where you do the day to day activities, management decisions are made etc.).
An LLC is likely to be a more efficient tax structure as a single-member LLC is automatically disregarded by the IRS for tax purposes and any tax liabilities pass through to the individual. As this is often viewed as a hybrid entity, it can be a tax efficient if your country of residence views it this way.