Same machine. Just different HDD. If I were you, get the one that you can afford and if you need to upgrade, you can get a 500GB HDD for about R700 in todays prices. Will be cheaper as time goes.
*****in A my friend! I got my PS3 about a year ago - 40GB from Makro..R3999 with 2 controllers - remember that deal?! ... installed a brand new 250GB SATA 2.5' notebook drive and been using that since!
new ps3?! heh.