I've heard a lot of stuff about Vanish. I've used it all year and once I figured out to use 5 wraps on the knot instead of 4, I had ZERO issues with breakage. Used in weeds, wood, some rock, docks...No issues with breakage and that included yanking a five pounder out of timber in 12 foot of water with about 20 feet of line out. Diameter is a little big and it's got a little memory (not much, but some), but it's plenty tough. I've got PLine spooled up now because I wanted to try it, but I'd use Vanish again in a pinch. YMMV
Perhaps I had a bad batch but let me tell you my experience with it was really bad, and it never even made to the water.
My bro actually bought it and at that point I had only read the horror stories and the occassional positive story like yours.
So I went to test those claims for myself. I took his newly bought spool (8#) and lined his Symetre with it. No problems at this point. I proceeded to tie on a crankbait and gave my "pull/tug check" on the line which is never overwhelming by any stretch. The line broke upon pulling the line.
I figured that perhaps I was too careless with tying the knot (I didn't think I was) so I retied. I was even more careful the tying the knot the second time. Not only did it happen again, but a third time. I will tell you that my pull/tug was no harder than a blue gill's take of a bait and I'm not talking about slabs.
I am very careful when I tie my knots and it is one area I take my time. I used the improved clinch knot, if anyone wishes to know.
Three strikes and you're out for me, and the line didn't even get wet. The next thought that came to mind were the many posts about how poorly this line performed for so many.
I am glad that it has been working well for you. Perhaps there was something wrong in its production and my bro bought a bad spool, who knows?
If one or two persons say "X" stinks, I'll make a mental note. But when you have so many people sharing their stories about how poorly Vanish (I call it poof now, because that's just what the fish will do...) was for them, you would have to wonder what caused so many to arrive at their negative conclusions about Vanish.
Don't use an improved clinch knot with floro, that may be your problem. I use a Palomar knot with floro, wet it down well with saliva, then slowly pull tight. I use the cheap BPS floro which recieves lots of complaints, but I don't have any problems with it breaking at the knot. If you're breaking at the knot then more than likely it's the knot that you are using. Do a search on Google on fishing knots using floro and you'll see that it is not recommended to use an impoved clinch with floro.