Here's how I feel about fluorocarbon. I really like it for bottom bouncing baits. (c-rigs, t-rigs, drop shots, jigs, crankbaits)
It doesn't have as much stretch and I really like this for setting the hook. You don't have to wail on it as much as mono and if you do wail on it, you get really positive hook sets.
It sinks and in situations like drop shotting or finesse stuff, the sink factor really helps to get it down in the zone faster.
It has a whole heck of a lot of sensitivity to it. More so than mono and in my own personal experience, almost as much as braid.
It is really abrasion resistant. You can drag it over wood, rocks, and it holds out really really well. Try dragging your braid through the bottom of rivers that are rock bottomed... :
To top it all off, it is virtually invisible in water. Some people will say that it doesn't matter. To me, it can't hurt though I still have not made a decision on how I feel. I don't really choose Fluorocarbon because of this property but it is nice to have.
I have never had a problem with knots. Lube them up real well, take your time trying them, and you should not have any problems either.
The really big problem for me though, and one that I can hardly get over? It has so much freakin', stinkin' memory! More so than most of the monos I have tried. It's not like braid where you can ball it up into loops, re spool and it sits perfectly as if it had just come out of the box (a little hyperbole but not much). So, to get around that terrible memory which bugs me so much, I usually just go with braid and tie on a leader of about the length of the rod, sometimes two when I am going to burn through a lot of leader (drop shots).
Carlos
Note: I should also add that I actually PREFER Vanish Fluorocarbon, something that most people hate. I have absolutely no problems tying knots and breaking off. The line memory is something I have come across most other types of fluorocarbons. Even some of the more expensive ones I tried like P-line, had even MORE memory than the Vanish I used LOL .
I do hear from others that some of the more expensive ones like Tatsu don't have as much memory and are a dream to fish. I just can't see myself paying out the ying yang for line though...