Now that the CBS Challenge (aka “The Challenge: World Championship”) is done filming its US version, the cast has come home, and a lot of them allegedly had a bad time. Survivor winner Tyson seems to take issue with production on episode 12 of The Pod Has Spoken podcast (jump to about 22:45). He said:
No matter what show I may find myself on in the future — years and years down the road, whenever, on whatever network, doesn’t even matter — Survivor challenge team is the best at putting together, and building, and creating sick challenges when they need to.

Then, his cohost Riley McAtee and guest Parvati Shallow ask him if this was a clue. He denied it, but said “any other Challenge show you can think of, Survivor does it bigger, better, and more proficient and more professional than any other crew out there. “
So, it doesn’t seem like he was too impressed with the production value of the upcoming show. Though The Challenge generally has much bigger competitions than Survivor does. Many of their games involve more simple elements such as climbing a rope, swimming, and solving a puzzle. The Challenge earned its reputation as a heights over water show for a reason. They put a lot into their competition, but they’re less predictable than Survivor.
If we look at All Stars or Spies, Lies and Allies, people did get hurt in the games. This isn’t unheard of on Survivor, but it’s less common. Of course, the games on Survivor can be as simple as holding a ball with a stick for a long period of time. The risk isn’t that great.
So I wouldn’t blindly believe Tyson, because his expectation for Challenge games are probably based on more simple Survivor games. But there is a good chance that people got hurt during the season and the quality wasn’t as great, because that’s just how The Challenge works.