I think that the "bad spool" comes from hanging on to the stuff too long like I do. If it has been blasted by UV for long periods of time it may actually become a little stronger at first or at least thats the way it seems to me. Trouble is it also looses knot strength at the same time and therefore becomes no good at all.
If a shop hangs the stuff where sunlight can get at it, in time it will "go bad". The glass windows will filter out much of the UV but not all of it. Solution...rotate stock, keep it out of the sun. Maybe we should insist that tippett material be dated so that we would know. I don't think that the manufacturers would like this idea...(its not their fault after all) but if one started, they would all have to follow suit...and then we'd know.
Another bad habit I have is carrying tippett material in my car where sunlight can zap it. I do carry it in a tin tea box though except for that on my reels and in my vest.
I'm going to check out Fog Hair if I can find it...I've used Maxima for years...and I find Rio to be good. IMHO its all crap but the only stuff we have so far...damn little progress having been made since nylon first arrived in quantity after WW II.
Ol' Bill