This boxset contains the CDs Oasis Xposed, Maximum Oasis and More Maximum Oasis (if memory serves me right!) which is probably the first thing you should check if you already own any of these CDs.
All in all its a fairly interesting set with one CD of interviews with the band and two of biographies. To be honest I haven't listened to them all yet as everything is unofficial and so features that very annoying music that is vaguely similar to the bands songs but enough so they have to pay for it. Nothing too groundbreaking is contained on any of the discs, the three postcards are quite good and the poster is just of one of the CDs artwork.
I would only reccomend this to extreme Oasis fans, otherwise save your money and buy something else!