Do you love big bluegill?
As I understand the science behind such things, the frequency of light that the line reacts to - that which causes it to "flouresce" - rapidly decreases in intensity below the surface of the water. Indeed, we know this to be true for the entire light spectrum. So, once in the water the glowing of the line we enjoy above the surface has no significant effect below. It tends to blend as well as anything else so the fish aren't spooked by it.
Fluorescent line has been around for a long time, and has kind of fallen from fashion these days. What it seems Vicious has done here is change the packaging to fit into the "$1 Rack" niche. Same sort of line, different way to sell it.
I've used the Vicious line, too, and have noted its ability to seemingly disappear in the water. To be on the safe side, I usually start out the day with a leader of 1 or 2 lb ice fishing line when 'gill fishing. I probably dont need to, as you note. In fact, I often end up with the leader broken off and just the main line tied to a hook.
I've never really taken any notice of the lines effect on catch rate. I'm pretty casual about such things myself. But I thank you for bringing it up.
Well....Im not really a "line head," myself. I usually buy whats affordable, at WalMart or internet sources like OverstockBait.com. This is why I tried the Vicious panfish line when I saw it... inexpensive. This said, most line comes across pretty much the same to me.
But my guess is that the yellow fluorescent color of the Vicious line is such that it isn't readily seen by them. This may have something to do with their color perception - it could explain a lot.
Trying something else in a comparison like that orange fluoro stuff could provide some answers.
i know a lot of anglers dont like to use braid because they claim it has visibility issues that allow the fish to detect the line in their environment. i use spider wire stealth and have actually seen my catch increase significantly because of the extreme sensitivity. mono just has so much stretch and lack of sensitivity that i actually will refuse to fish with it any longer.
the occasional bass that hit the panfish bait could actually be horsed in if needed.