I have posted numerous times about my experiences with fluro and I have yet to have a negative that I couldn't control. I am a fan of Seaguar InvizX, and AbrazX or Red Label for my spinning rod line, (anything under 10# test), Here's my own personal rules for fluro Rule #1 - Stay away from Vanish line - it's junk. Rule #2, Seaguar for 8 & 10# line, Berkley 100% for 12# and up,or, Viscous 15# and up. Rule #3, Check and retie often. Rule #4 use a reel that has adjustments for flurocarbon (see shimano line of reels, I personally like the symetry or the saros) Rule #4, Do NOT use on top water baits because it sinks. Rule #5 do not deviate from rules 1,2 &3. These are my OWN rules for me and it works extremely well.
Line Diameter? No problem, no complaints.
Memory? Different brands are better/worse but above mentioned works WELL for me.
Durability? How do you fish/where do you fish if it's rocks then all lines have issues some are worse than others but again not really a negative for me.
Knot strength? I cut my hands repeatedly when trying to break off a stuck shakey head! The other day someone asked about knots - read it - allot of good insight there.
What you gain is sensitivity and line disappearance (to an extent) and ability to get bait to drop straighter down when casting to help eliminate the pendulum effect because it sinks. You get greater depths on crankbaits as well.
Cons: Cost $$$, having to experiment to get your own set of rules that work.