Excellent thread - let’s talk criteria for the application:
My preferences:
1. Must be on your person at all times while climbing, descending, and setup in your hunting position.
2. Must be readily accessible for retrieval by either hand, in the event one hand or arm is injured in a fall and no longer working.
3. Must be a fixed blade so that your one good hand doesn’t have to open & lock the blade in place when deploying it.
4. Must have excellent sheath retention so that there’s no risk of it coming out by accident in a fall or if inverted.
5. Must be compact & unobtrusive where you locate it on your person so it doesn’t get in your way or snag ropes or webbing when maneuvering around the tree.
6. Must be scary sharp to be able to slice through tough ropes and webbing when necessary.
My choice: ESEE Izula in S35VN steel with retention kit, honed to razor sharpness, and kept on saddle belt in abdominal region.