I am a long time fan of this British 'Alternative' comedy troupe so my review is BIASED....
This Blu-ray release is NOT a complete 'series' collection, stick with the DVDs for that.
This is basically an early episodes collection produced for the BBC's Channel 4 which is pretty much the 'Best Of' if you prefer the early stuff.
The early extended film-like episodes are included on disc 3.
As for quality, Audio is noticably better, Video for the episodes is the American NTSC 480i, Standard Definition. Without any restoration the video is marginally better than the old DVD sets.
I also have a PAL DVD British complete episodes edition, it doesn't upscale as well as the NTSC version.
So, if you are a FAN, I would recommend this release, if you are a casual viewer go with the COMPLETE Series editions.
Best to have twice as much content I think.