The Lonely Shepherd is in my opinion not even close to his greatest songs. Still wonderful, as is all of Gheorghe's music, but the song is probably overpopularized. If you like The Lonely Shepherd, try listening to his other songs; it's well worth it.
I remember being blown away when I bought a couple of Zamfir albums out in Romania in the early 1970s. He was an exceptionally dynamic artist. I'm a little less impressed with his more recent work. He's technically accomplished and the pan pipes are good to listen to, but he's lost that final touch of excitement. Of course, it could be that I've been unlucky in what I've listened to - or that I am remembring his Romanian tracks too kindly. Either way, he's good.