With Survivor and The Amazing Race taking the summer off, a trio of cable shows are out to fill the endurance challenge-based reality series void. TNT offers up the one-two punch of the Dwayne Johnson-fronted The Hero and 72 Hours (which air back-to-back on Thursdays at 8 PM and 9 PM respectively), while the obscure Reelz network counters with Race to the Scene (Thursdays at 9 PM). Which of these shows walks away as the sole survivor? We pit them head-to-head in five key areas: