I've heard a lot about these fins, but only had a chance to test C4s. All the reviews from people on the hybrid fins that I've read have either been from people who've gotten them cheaper/free, or those who've never used a fibre/carbon fin before. I'm looking for an honest comparison between the two blades, so if you've used both, and didn't get either for nothing (or cheap), I'd appreciate a few words on them 
Cheers
Cheers