Chinese brands = non-adjustable and/or horrible eye relief
I have a Huang ACOG I got through a trade and it has less than 1" eye relief, as in the space your eye has to be in behind the scope to focus properly is a 1" range, not that you have to be within 1" of the scope.
G&P makes the best 4x ACOG short of the real thing (yes, Chinese, but Hong Kong, not mainland, so in a different category than "Chinese" brands.)
As far as I know ACOG's only have an export ban from the States if they have Tritium in them. Holosights are export banned totally. Aimpoints I'm not sure on. Export ban doesn't mean you wont get it, it means you might not get it but if caught you will also find it more difficult to fly within the US as you will automatically be put on the terrorist watch list for trying to arm terrorists with US equipment. ANYTHING and EVERYTHING that leaves the continental USA that has a ban AUTOMATICALLY lands in the hands of a terrorist, period, end of story. At least according to certain US government policy makers...