I use them....
Frog Hair are good so are the Orvis super strong, whatever brand I use they have to be supple and not be a short taper with a load of floppy leve stuff on the end. In the latter I Use 12' for dry flies as standard with a bit added in most situations, and where I need a shorter leader I use the 7.5' leaders and build the rest. For wet fly or multiple fly rigs I use 6' tapered Super Strong and build what I need from there. Don't tend to use braided loops at all these days for anything under a 7wt line, #3 - #5 I use about 12" of appropriate diameter butt material nail knotted to the end of the flyline and I put a perfection loop in the end of it to which I loop to loop connect my tapered leader. On my heavier lines I end to whip & aquasure loops.
Cheers
Ben