Personal preference - I'm afraid I don't like Krystonite, not because it isn't a true flourocarbon but because I've had it break on me on more than one occasion.
I use mono now, Suffix Xcelon to be precise and I am much happier with it, infact I can't fault it, supple, strong and a good diameter to breaking strain ratio.
I use Shakespeare Sightfree when I need a flouro hooklength or Korda IQ.