Just to let you know what you're getting here- JSA comes on a bare-bones disc with no extras, while I'm A Cyborg has an hour-long interview panel with the director and a brief making of featurette. The discs are packaged in one case about twice the width of a standard DVD box, and come in an outer slipcase with the same artwork. I should mention that there exists a separate edition of JSA which does include a bonus disc.
Each of these films is extraordinary, and should be first viewed with as little information as possible. There are other reviews that detail plot and the like, but if, like me, you approach either of these films after seeing Park's more lauded Vengeance films or the recent Thirst, you should find them as enjoyable and rewarding a viewing experience as his other masterworks. Also, it's a very cheap price for two films that retail for higher amounts separately.