I have the rings on some of my furled leaders. I will say they are very convenient. I also have furled leaders with mono loops. The advantage of the ring is it's easier to remove/replace tippet since the tippet doesn't "bite" into the ring like it does with mono loop. Also, when you cut the tippet off you don't need to worry about cutting the ring like you would with the mono loop.

The rings are so small they actually float in the surface tension without being treated. I didn't think I would like them at first but I've grown to like them for many applications.