While I use the uni to uni knot for joining a lot of lines, I have had it fail. Be very cautious using it to join fluorocarbon to GSP lines...I broke off three silvers in a row the year before last.

Talking to some people in the business, I found that the fluorocarbon-superline junction can be a tough one to make work...something about the lack of stretch from both lines or the density of the fluorocarbon. I've had no problems with the mono to super line connection using the same knot.

The knot itself is strong-- the skipper on a charter I fished this year out of Sitka uses it to join his very expensive color-coded GSP braid to plain braid. We caught lots of kings and halibut to 70 pounds or so without a knot failure.

Dennis-- I like to use hi-viz super lines and tie six feet or so of mono to keep from spooking fish. Whether it really matters or not is something else again, but that's why I do it.

Keith