They are just somewhat harder to export from the US than other items... This one (512) cost me 443$ including Priority shipping. Bought a 552 back in 2005 from the US also without any trouble.
Edit: Yes, they are totally worth it in my opinion. 200$ less than an Aimpoint and they do just as good of a job.
hmmm, well once i am back into the school habit i may just have to invest in a 552, i really like those ones.. do you have any recommendations to not get one or any better ideas?