European delivery (aside from having to stay within the manufacturer's recommended speed and RPM limits while driving on some of the best roads and highways in the world) is a fantastic way to buy a vehicle.
But like Randy03 said, it doesn't make sense to buy a German vehicle and then import it to the states. Aside from the cost issues I'm not positive you can buy a US spec vehicle for delivery in the EU or elsewhere. So you may also have to deal with the vehicle meeting US safety regs.
From this page it doesn't appear that those on temporary assignment are eligible for the program. There probably are ways to skirt the actual purchase restrictions but the insurance and registration is for a finite period of time; usually a couple of weeks but I know you can extend it for months with additional cost.
The following information is specific to BMW's program.
http://www.bimmerfest.com/wiki/index.php/ED_Summaryquote:
You may keep your car in Europe up to 5 months after delivery (there is a 19% penalty tax if your car is not exported within the 6-month period). Cars financed through BMW Financial Services must be exported within 90 days. Cars leased through BMW Financial Services must be exported within 30 days.
quote:
Your new BMW is restricted to private use by tourists (including business travelers). Persons working in Europe on temporary or long-term assignments are not eligible for the special customs license plates issued under the European Delivery Program.