I got a really good PM asking me what I use for leader Material on my tip-up set-ups for fishing livebait. Since I made a recent change I thought I would pass on my testings from last year.
I have never really used leaders while fishing pike. For the most part, I used quick strike rigs, that did not require a leader. However, sometimes you stumble onto a better option. Last year was a tough year for pike and I was forced to look for options to get bit more.
Last year I tested Crystal Fireline on my Tip-ups while targeting Pike. Crystal Fireline if difficult so see in the water and it out-produces all the other combinations out there that I used previously. So, if you are looking for a nice leader material you may want to give it a try. Like I said, we had excellent success with it last year, both in terms of strength as well as number of bites.
While using quick strikes or dead bait, I do not use the Crystal, but on my live bait set-ups it was deadly last year. Something to try this year if you are looking to get bit more 
I still use Berkley Vanish Flourocarbon on my walleye set-ups but change them out to Crystal Fireline when we are targeting Pike/Walleye together.