Having had a few BMWs in my lifetime, I can say that the build quality of the X5 coming out of the USA is not as good as the German build cars. Even the 3 series from South Africa are better built. BUT most of my complaints extend to the poor interior materials.
1) The surround to the Sat Nav screen creaks
2) The hard plastic lower B pillar trims are a joke, I have seriously seen better on a Kia
3) Why can't BMW make a tailgate which doesn't rattle?
American built = poor build quality I'm afraid.
The much maligned Range Rover Sport is better built, I had two before the X5. It won't be long before I look at another, the cheap build quality of the X5 is rapidly turning me off BMW.