I have never used a stronger tippet. This stuff is fantastic for abrasion and break-strength. It's supple and stays straight with no propensity to coil. I used the 4x and 5x for anadromous trout and steelhead on the Great Lakes tributaries. In the past,3x was the norm. For Euro nymphing, I typically use 6x and this stuff does not disappoint. HOWEVER... the coating on this line must be super slick. If an improved clinch is used you may find that it will slip and you end up with a pigtail, lost fly,
and lost fish. I recommend the Pitzen (16-20) knot or the Davey. it happened on many occasions so I am sure its the tippet. It could well be that what makes it good for strength, makes it bad for "slippage". With a minor adjustment in knot tying you can enjoy the strongest tippet available.