I love them. I experimented with ones made frm tying thread, tipet material and even silk sewing thread. The ones made from UNI 6/0 thread work the best for me (trout) They last an entire season and then some with a few changes of the tippet. I tried to convince some og my fishing buddies but they prefer the knotless leaders. I guess it's to each his own...

I make my own and can get three 9' leaders from a single 2 dollar spool of thread. The jig set up cost about 5 bucks worth of scrap wood. I can build furled leaders much faster than hand tied leaders. They don't cost me very much more than time....

The only time I don't use them is for nymphing on streams where I need to adjust the leader length ot depth often. Then it's easier and faster to cut into a knotless mono leader.