I used Fireline for a few years and loved it, but.....I got some serious cuts on the fingers then hand and just had to stop using it. Way too thin for me. It took 21 staples to close the back of my hand the last time I used it. A striper took off with it sliding across the back on the hand while holding both handle and rod to keep my rod from leaving. The drag sang a song, smoked some, and blood flew. The knot problem is solved by using a double Palomar or Trilene Knot with 6 wraps and 1/2" of tag. Melt the end of the tag to make a button for extra insurance. I don't remember ever getting a break above the knot. Casts nicely, and made a great winter line. I rarely if ever attached a fluorocarbon leader. Bass didn't seem to mind that line. It's so slick you have to tape in down on the spool.
Jim