There was a great deal of discussion on this KF thread: Hook Knives...don't bet your life on them!
I would be interested in knowing the results of a comparison test, that you could easily do. The test would involve taking a piece of old kite line into a kite shop that sells the newest model of the DaKine double-bladed hook knife. Have a person hold the kite line stretched out firmly, with their 2 hands. Then, first cut the string with the knife under discussion, and then do the same thing with the DaKine hook knife. Let us know which knife cut the line with the least amount of force exerted.
Also, post the result on the above mentioned thread. It is nice to keep all the data in one thread, for future reference.