I didn't read the original, but the updated edition includes a preface, written by Bourdain in 2000. It basically is a little update regarding his activities since he wrote KC, and that he had been doing less at Les Halles.
IMO not worth buying if you have the previous edition. Just pull it off the shelf at your local bookstore or library and read the preface.
And it's disappointing the Kindle edition does not appear to be this new version...this sort of thing is getting OLD Amazon...quickly. Just how hard is it to put out the most current version since the ebook is already out there. I know, I know, blame the publishers...that is your problem Amazon, not mine...I am YOUR customer, for now anyway.