Hide glue is a generic term ,there are different collagen type glues made out of different animal parts Knox is a combination of bone and other parts , different types have different gel times & strengths for different applications , I think every body likes what there comfortable using ,I have used rabbit skin glue with no issues and some claim it's not the best to use for sinew and have used different grades skin glue & clarified versions that I really like and played with different gel times , they all work but I prefer the slower gelling clarified ones , there are a lot of different opinions from different type bowyers !