Completely different designs with different missions in mind.
The RC5 was designed for an E&E SERE environment where use as a survival tool was stressed over all else, with a very minor combative role or application.
The STS5 from Bark River was designed with input from USMC Force Recon. with a mission requirement as a Close Quarters weapon. with primarily a defensive combative purpose in mind.
The STS5 will perform most survival blade tasks, but the sharpened back edge will eat up batons in use and will make many other tasks more difficult.