Robert Redford looks pretty damn cool in it. Sure his blond hair is very 70's, but the outfit could easily be slightly updated today and still look great.
One thing immediately apparent when watching the movie; they just don't shoot a film this way anymore. Plenty of long shots, camera angles held for what seems to the modern attention span a long time, it's a different experience than a modern cut and jump film scene. But it manages to hold your attention. The long scenes with a static camera angle develop nicely, the scenery around the actors looms larger.
Oh yeah, and it has Max Von Sydow in it. Enough said.