Do you want to register an LLC or a Corporation?
Advantages of a LLC
The LLC is a unique type of company. It is a hybrid between a partnership and a corporation. The advantage for non-US residents, who have no US sourced income is that a Delaware LLC is totally disregarded for income tax purposes by US tax authorities. A Delaware LLC pays only one "tax": the $300 per year Delaware franchise tax.
An LLC's profits "pass through" to the individual owner. The advantage for non-Americans who do not file a U.S. tax return is that the LLC's profits pass through to the LLC's owner but the income is not taxed by the U.S.. It is still your responsibility to report income tax within your own country.
Advantages of a Corporation
If you DO have US sourced income then perhaps a US corporation is the better choice. You will be required to pay tax on income earned in the United States. Therefore having a corporation can simplify things. The disadvantage of having a corporation is that it is taxed on worldwide income, not just US income. However you can talk to a US accountant about minimizing this tax.