I began using Silver Thread co-poly from the time Bagleys began importing it from Japan. I used nothing else, eventually moving from the blue label to the SST/AN40. This changed last year when in a fit of madness I bought a spool of Seguar InvizX in 20lb for pitching jigs, and actually won a spool of STREN Fluoro in an online contest in 17lb. I switched to PowerPro braid on my spinning rigs for dropshot/shakeyhead fishing. So far, I'm not sure the fluoro is a bit better than the AN40, although I do like the PP on the spinning tackle. It wouldn't bother me a bit if I had to go back to copoly on all my baitcasters. In the years I've used it, it's been supple, tough, and I never lost a fish due to line breakage.