Tibs,
I assume you're talking about Xtreme Fiber Blades on a Honey Bee FP? If so I have had a set on my HBFP for many months and love them. They made my Bee more stable, and very tough and non-flexible (good thing).
If you're talking about Xtreme blades for the Big Lama, I don't like them. They may be tough but are too flexible, sort of like flopping around the shaft like a wet noodle, and too much upward coning.