First of all, I just want to mention that I was always interested in GITS SAC, but between the other expensive collection floating around and the fact that it only airs once a week at 4am, I've never really had the chance to take a closer look. That is, until this convenient, affordable set-up.
Well, anyway, GITS SAC revolves around the investigation of a cyber-terrorist known as the "laughing man." Throughout the series attempts are made to stop this heinous criminal only to reveal that the plot is much thicker and deeper than first imagined.
Along with the overlying plot, stand alone episodes act as avenues for character development, philosophical questioning as well as world building. Perhaps two of the better (or at least entertaining in my point of view) episodes consist of Batou's backstory while investigating a fighter and the tachikoma's consistent questioning of life and death.
Though these stand alone episodes offer much in the way of development, they have a habit of breaking the pace a little. If you are not intending to watch large chunks of the series at a time or in reasonable succession, important details can easily be forgotten.
All and all, GITS SAC offers espionage, action, philosophical debate and characters that you can't help to feel for. Just remember one thing while diving through the GITS SAC world: Nothing is at it seems. And one other thing: it doesn't hurt to keep the remote in hand to rewind to what you missed.