also, if it does corrupt you can just load up your game from the corrupt save, then switch it with a different mem card (still with SCIII on) and save from the option menu... from there on your save is no longer corrupt. I did this myself, so no worries. Also, the glitch only happens when playing chronicles of the sword. It's not as horrible as people think, as long as you know the workaround.
also, I would wait for a minor price drop sometime since it looks like it may be dropping soon.