Really? at 56 grams? I see they have a keylock nose, which isn't a big deal to me, and they're well priced, but why are they the best?
Maybe I should phrase it thusly, "Why are they better than Trango superlights which are shockingly lighter at only 41 grams and can be utilized in lots of places where a light weight unlocked carabiner would normally be utilized.
And why are they better than the DMM Sentinel HMS which (like the Superfly) weights less at 54 grams and has a larger gate opening (nice for walls and multiple party clusterfriggages). Most importantly when your buddy drops his only belay device from 12 pitches up, can be used for rapping and belaying with a Munter Hitch? "
Perhaps you mean trango superfly?