Pendragon

If I'm thinking about picking up and running Pendragon, does it matter what edition I go with? I'd prefer having an actual copy of the book to PDF, but it looks like even the latest is rather badly out of print so I'm probably going to have to get an electronic copy no matter which one I pick. 5th looks fairly good, and it was written by Greg Stafford, so am I safe just picking it up? Or is this one of those games where the later editions polish all of the heart out of it?