I have a furled leader from Feather Craft with the stainless ring on the end. I use it on my 8 wt. It doesn't get or hold kinks. I only use 2X Fluorocarbon and when the tippet gets eaten-up enough, I bust it off and loop a new 3 foot section on. I don't like the tendency of mono butt sections to hold coils. It ruins your presentation. Sometimes you get a coil or a kink that just will not come out after streching. I really like the performance of the furled leaders. I don't see many disadvantages of them besides cost. None of the shortcomings of them (visibility and spray) have manifested themselves enough to disuade me from using them on trout or bass. I think of them as an addition to my fly line. Just looping on tipet is a great, easy modification. You can't beat their presentation, even on nymphs, because they are more limp and they straighten right out for use. A big trout on Penn's C&R wrapped me tight around something deep. I ended up busting the leader above the ring. So I haven't fished on for trout since then, but will replace it this winter.
If you are afraid of the leader's visibility, add a 1 ft hunk of 2X larger tippet and then down to your normal tipped. You can do 4 ft. tippets with that. I did this, being overly cautious, but went back to the normal configuration. I didn't need any such set up for the conditions. But if you do, know this trick. It works and will present a fly in a critical situation better than mono.
Syl