This is a good place to start. In the end you will need to work directly with a good tax attorney. for your needs I would recommend Price Waterhouse Coopers or KPMG.
but here are my concerns for you.
1. Tax Treaty: No matter how you cut it, there will be tax treaty consequences of establishing a foreing entity in the U.S. What you attorney apparently neglected was the effects of the tax treaties on corporate or business income, world wide. If you register your company in the U.S., then after 183 days of physical presence of any of your sales reps, storing of product in warehouses, and or exploiting the U.S. market place (makes sales and signing of contract for services etc), then the company is treated as a resident company for tax purpose and there exists, a potential of exposing your company's world wide income to u.s. taxes.
Most country tax treaties are closley similar because they use either the U.S. or UN tax treaty models as a template.
So to protect your company assets world wide, you would want to form as a seperate entity eventually in the U.S. That entity could be an LLC or a C corporation.
Take ICI paints for example: ICI (Impericakl Chemical) is a large UK corporation. When they came to the U.S. they initially started out on E-trader visas operating registered in the U.S. They eventually incorporated by acquisition, acquiring National Starch. As a member of the HR Team in the role of international immigaration and cross boarder tax, we planned and explored expansion of business operations, from the U.S. company into the Carribian. At every turn it became evident, that because of consistent tax laws world wide, it became better to incorporate in foreingn countries seperately, even if the Parent was from the UK.
When you incorporate seperately either as an LLC or C-corp, you maintain seperate U.S. operations, and have a seperate U.S. Payroll, and there for you offer further protections regarding world wide income and cross boarder tax issues. Your corporation is only liable for U.S. sourced income, or income derived world wide that is essentailly connected to a business located in the U.S. Without a seperate corporation, as soon as you have a sales rep who can emdemnify the company signs contracts and has accumulated six months of operations in the u.S. then you open the door to potentially have world wide income taxed by the U.S. (all income world wide that can be determined to have arisen world wide from the u.s. operation)
You have 10 million dollars world wide to protect from taxes.
Now whether or not you incorporate in the U.S. as an LLC, or a C corp is largely a subjective matter. LLC's are states inteites that are taxed as either corporation, S-corp, single owner (disregarded entity), or partnership. Since you are non-resident aliens the S-corp is not available. So your LLC would be taxed as a passthrough entity (partnership or disregared), or as a corporation.
The primary two reasons people form corporations in the U.S. is to gain a tax advantage and to protect personal assets from litigation and liability of company failurs and law suits. A C-corporation gives the best liabiltiy protections, while the LLC gives the best tax protections.
However with both forms, LLC or C-corp, the protections for liablity can be piereced. (piercing the corporate veil) The protections are pierced for things such as: public trust fund obligations, which are taxes. However it is also pierced for liability issues related to business operations, where presonal gaurantees are proviced to obtain credit, or where the corporate officers and owners have direct control over an activity or operation. So in this regard, your personal assets are better protected with a C-corp. this is because the LLC is a passthrough entity to the owners personal tax returns.
As a foreign owned LLC, each owner/partner in the LLC would incur a tax liablity in the U.S. for all U.S. sourced income. this is defined as income associated wtih a u.s. based operation or business activity located in the U.S. The tax savings for the LLC for Residents and Citizens versus the C-corp is that a C-corp has to pay taxes on net profits in the form of corporate taxes, and then it pays emloyees and owners a paycheck and reports income ona a W2 form, where it must then have taxes paid again by the employees including SS and MC withholding.
The tax savings for citizen and residents becomes only paying taxes one time on the individual return. But they must pay their own SS and MC taxes in the form of Self employment tax.
As Non-resident owners of an LLC, not taxed as a corporation, you do not have to pay self employment taxes. But you still have to pay payroll taxes for any employees, and for owners, and each owner pays income taxes on their share of net profits originating from U.S. sources, and if the company does international business form the U.S. location, from that worldwide income as well.
The complexity of filing taxes as an LLC partnership or as a C-corporation is a fairly level playing field. The complexity comes when you decide to become a publicly traded company on the stock exchange. Also no matter whether you are an LLC or C-corporation, when you start doing additional investments outside your routine basic corporate or business activities additional forms and processes are always required. Fore example: complicated real-estate deals, reinvesting profits into securities markets, etc. In some respects LLC taxes can become more complicated because of allocation rules for expenses, and income, owner equity, and good will.
So what you save when you form an LLC is really only the MC and SS taxes. But this is worth 15.3 percent of net profits. (percent of which is tax deductable), so net savings for your situation is about 8 to 12 percent.
With 10 million in annual revenues and 200 worldwide employees, you are at the upper margin of small business in the U.S., by definition (http://www.sba.gov/) Strategically, you would need, I would think, to think more globally about the incorporation style beyond the mere saving of income taxes and Medicare taxes for the U.S.
I tried to quantify if for you, but it is still a subjective call.
Here are some links and information that may help:
Taxation of aliens: http://www4.law.cornell.edu/uscode/uscode26/usc_sec_26_00000871----000-.html
Third party outline of incorporation as LLC which includes statements regarding aliens: http://www.us-llc-for-non-residents-of-the-usa-incorporate-llc-in-us.offshore-companies.co.uk/
LLC tax return documents: http://www.irs.gov/businesses/small/article/0,,id=158448,00.html
C-corp tax return documents: http://www.irs.gov/pub/irs-pdf/f1120.pdf
Immigration issues: Without establishing an entity in the U.S. your only visa choice for employment purposes is an E-1/E-2 treaty trader visa. However once you establish an entity, either an LLC or C-corp, you can now sponsor people for any available work visa except for an L visa in the first year. This includes H-1B, F-1 and J-1 students on curriculum and optional practical training, and O-visas, and TN visas. After one year of operation in the U.S. as a sister or affiliated corporation of the parent, you can start bringing workers in to the U.S. to work in the U.S. facility in status L1/2 visa.