Rather than reviewing Pilgrim's Progress, which is clearly a masterpiece and of immense spiritual value to Christian readers, I would simply like to commend this Oxford World's Classics edition.
Having read and worked with a few different editions, I favour this one for three reasons. First of all, unlike some other editions, this one doesn't miss bits out. Second, Bunyan's language is largely unaltered. While updating the spelling and vocabulary undoubtedly makes Pilgrim's Progress more accessible for a wider and younger audience, it also tends to cover over some of Bunyan's teaching points. If you can cope with having to re-read some sentences and check the odd endnote, there is simply more gold in this original text than in many of the touched-up modern alternatives. Finally, this edition has Bunyan's own marginal notes, helping the reader to recognize Biblical allusions. Lots of editions have someone else's notes, but what could be better than the original?
Please don't think, by the way, that this edition is hard to read. It may be slightly harder going than a more modernized text, but Bunyan's capacities as a storyteller must not be underestimated. He had a way with words and a spiritual insight that few have been able to match. When Bunyan preached in his own day great crowds of people from all walks of life flocked to hear him - from this edition one can see why.
Overall, John Bunyan is the one worth listening to (rather than any editor) and this Oxford World's Classics edition seems to put his text and his intentions front-and-centre. I think W. R. Owens has done a super job, making available the towering masterpiece of someone who was both a heroic Christian and one of history's great popular communicators.