I only have the Riffe.
For brain drilling the shape of the Riffe should be easier entry because I have knife with blade shape like the Cressi and it has more resistance when used on head drilling.
The side of the knife does not really kill the fish, it is the pointed edge and the slimmer it is at the front, the easier it will penetrate the hard head fishes and when one move the knife front/back like changing gear on a manual transmission car, then one wil do more damage with the sides of the knife.
I can cut the 500 lbs coated cable shooting line with the Riffe serrated edge. This is important for me.
Rust, yes Riffe knife seem to develop rust faster than most knifes I owned but I can understand that, to be very sharp the carbon content of the knife has to be higher and no choice but it will rust easier than say SS 316 or 304 blade , which can't retain sharpness too long. The 17-4 spear shaft is the same, it will rust. Take a strong magnet and if it will stick decently well to a blade, that blade has higher carbon content. Trade off must be made.
I have gone thru 10+ knifes ( mainly scuba diving knife though, including titanium blades ) and so far the Riffe been the most suitable for spearfishing and I like the long one, I think it is the deluxe ( not the short stubby one ) because of the size of fish I have to brain drill.
One important and simple item on the Riffe knife which is very important : is that strecth bungie on the handle. This act as double lock to secure the knife on the sheath and most importantly when trying to grab a big fish or a strong fish, you have two free hands. Let the bungie circle your wrist, it won't come off and when you managed to grab the fish properly, it is ready for head drilling. Its very useful that bungie thing. Mod the Cressi to have a bungie, that will be nice.
Looking at Cressi Killer, it share the same rubber clip like a Riffe at top of the sheath to secure the knife from falling. If one is to wear a knife on the hand/wrist, that rubber clip is not as strong as one would expect ( both Riffe and Cressi ) because the knife butt usually will face the fingers for ease of use. This way , most of the time the knife will not be aided by gravity during a dive, that rubber clip is the only thing keeping it in the sheath, this is where the bungie will help as second method of keeping the knife in place, even at the worst turbulence. Most of the time I do not even use the rubber clip but rely on the bungie alone when securing the knife to the sheath.
I don't oil or sharpen my knife, I sell cheap after every two years and get a new one.
That wonderful serrated edge of the Riffe knife that can cut 500 lbs coated cable its a b*tch to sharpen due to the complex shape, but it is worth to have and I am not patience when sharpening those serrated edges. If I can't cut cable, I loose more money , because it wont be just a shaft with slip-tip that has to be sacrificed, I have other gear at the very end of the cable shooting line meeting the swivel to the spectra reel line. So, if I have to cut cable shooting line, I must cut a few inches before its end. I don't use mono shooting line.
I think the Cressi can cut 500 lbs cables too if the blade material is suitable for the job.
IYA
