GSM Samsung S3 - where to purchase?

Hi

I want to buy a Samsung Galaxy S3 smartphone.. In Belgium the price is fixed across the retailers at €649, whil in the Netherlands I can buy it (unblocked) for €483.. is there any reason for this price variance other than the general nonsense of the Belgian market or am I missing something.. is there any risk associated with buying in the Netherlands as opposed to Belgium.. and then using a Belgian SIM?

I'm in the Netherlands at least twice a month for work so there is no additional fuel costs etc in buying there as opposed to here.

Thanks

XPAT Concerned at being Ripped Off in Mechelen.