This release was really well done, Picture and sound quality are flawless, DVD authoring is excellent, 4 episodes per disc avoids the need for excessive compression and retains the excellent quality of the source material.
as for the quality of the show, i loved volume 1 and volume 2 seems even more surefooted, the characters are even more well rounded than before.
it looks like they're going to release one of these sets every year, in which case i can't wait for 2010!
whatever format prisoner was shot on has aged amazingly, 30 years on it now looks better than many mid/early 90's tv shows (EG: a touch of frost) which now look quite grainy