John,

I use Seaguar CarbonPro,Seaguar GrandMax, and P-Line CFX. Never had any
issues with breakage outside of issues that were my own fault. Like not
properly wetting the line before cinching down my knot. Vanish is
another story. The stuff is absolute garbage, and if I could find the
email from Berkley that they sent me in regards to the issue, you would
see a direct quote echoing my feelings of Vanish, right from Berkley.
I fish fluoro through zebra mussels daily, with tubes, crankbaits, and
spider grubs, and only time I ever break my line is when I get lazy and
do not retie. I use all the way down to 2lb test for Browns and
steelhead in the winter if the water is crystal clear, and again, never
have an issue with breakage. Also, Frog Hair fluoro has proven to be
very strong, but it is very expensive (like Grand Max.).
Trust me, after using Vanish, I was very very down on Fluoro, and was
ready to switch back to Mono for everything, or P-Line fluoroclear, but
since committing to Seaguar and CFX I wouldn't hesitate picking it up
during a tournament with money on the line.

Chris