i have had very good performance from P-LINE flourocarbon and P-LINE flouroclear (i really like the flouroclear) . never had a knot fail and i can only remember 2 break-offs, both could actually be attributed to "gill plate cut-offs" from big stripes on jerkbaits. not counting all the stripers that stole crappie minnows , sinker, floater and hooks on 4lb test lol.
the flouroclear is value priced, stays fairly supple and memory free.
i use a palomar knot and as metioned above i wet the knot heavily to prevent the knot burn to the line.

ive never used the seaguar invisx on a reel but i will tell you it is the best leader material ive ever used for livebait fishing for stripers. it seems to be fairly abrasion resistant and i dont see how anything could ever see this stuff underwater, it truly disappears right below the surface so i can imagine it is undetectable at greater depths/lower light. it seems to be fairly soft and in my mind makes a difference in lower resistance to the hook allowing a live shad to move more actively, i would think it would have the same effect on a lure?

a well lubricated, well tied knot is probably going to help more than anything though.