When using a sensitive rod is there a noticeable difference in slack sensitivity between the two? I'm talking stuff like a weightless senko, fluke or worm falling on a slack line. Do you think it makes a difference and do you think use of hi vis braid can make up the difference? 

I use straight braid in green, braid to fluoro leader, straight fluoro and hi viz yellow to leader. I won't go into specifics for how/when/where and why I choose to use each of them, but they all have their place in my opinion. I will try to answer your question the easiest way I can. On longer casts with slack line, I feel like there is an advantage as it relates to sensitivity with straight fluoro. I think it is negligible when the distance is shortened (think flipping or pitching) or their is enough weight on the line to keep it taut. 

Flouro is more dense and a lot stiffer than braid.  So straight fluoro will almost always have more slack line sensitivity.  

 

However, if you're using a hi-vis braid, then you don't need the slack line sensitivity.  That's the point of high visibility, is being able to see the action, rather than feel it.  

 

I prefer the hi-vis braid when using light line, as light fluoro doesn't conduct vibrations well anyway.  It's my preferred choice for finesse fishing.  When going to a heavier line, the advantages of straight fluoro start to become more important than high visibility, like when fishing worms and jigs in deep water, where you won't see much line on the surface anyway.  They're two tools that accomplish the same goals, but in different ways.  Therefore, they each have a purpose.  Kind of like a screw and a nail.  Sometimes you can use either.  Sometimes one is superior to the other.  But both will always have a time and a place.

As far as slack line goes, fluoro has more sensitivity. 

 

Check out the 2:57 mark.

 

 

Personally, I use high-vis braid to fluoro leader for stuff like Wacky Rig and Ned Rig. For Texas Rigged soft plastics and jigs, I use straight fluoro 99% of the time. 

1 hour ago, Bankc said:

However, if you're using a hi-vis [line], then you don't need the slack line sensitivity.  That's the point of high visibility, is being able to see the action, rather than feel it. 

 

   ^^^ This. ^^^                    jj