Well, if you want to be technical the 4 pring shows off MORE of the stone better b/c you can get a real good look at the side of the diamond, but the side isn't really that impressive, and on lower color/clarity grades it can show off something that perhaps wasn't visible on the topside. Some mall jeweler (ack!) told me that a six prong will block some light entering in, making it noticably less bright and sparkly, but the good people here on this forum kindly informed me that he was on commission crack cocaine and that topside there will be no difference at all. I'm going for 6 prong b/c it just protects the diamond more from popping out (a rarity in a quality ring, but why not), and from bumping into things and getting slightly chipped (I hear that happens more often). It's your choice. I say browse some jewelery stores and see what you like (even though most of the time the diamonds are crap, it gives you an idea). Good luck!