J Francho, I agree as well.
I use fluorocarbon mainly for the feel. I was never a big fan of braid, so the closest thing on sensitivity is fluoro. But from what I understand about making line, once you add something to make it a UV or hi-vis line, it takes some other type of cystal or coloring. May add more stretch, knock down some of the abrasion...I dont know.
I'll still try it out though, I do a lot of stream fishing in my part of PA, and sometimes I like a 6lb hi-vis line. I just hate using fluorescent mono's.