To add to what Warren has stated. Furled leaders have little or no memory so you don't have that nasty slinky hanging off the end of your fly line. A furled leader can be cast just like a fly line increasing accuracy. Mono makes a more aggressive leader than thread and will turn over larger fly's. One complaint about the loop to loop connection is the tippet loop closing up making it hard to change tippets. Furled leaders will last at least a season if not more, you only have to change tippets to match conditions. Both thread and mono leaders can be treated with floatant to keep them on the surface, the mono will just have to be treated more often. If you would like to try one pm your mailing address to me.