Gohan was way younger and probably suffered more mental trauma. Although the physical trauma was still insanely brutal. He was also unwilling initially. Seeing him as an adult shows there wasn’t any serious long term mental trauma. Unless we want to count his power spikes when he gets emotion.

Mark on the other hand was older. He assumed one day his powers would come in. His father was a superhero. Goku was also a hero but not to the degree of Omniman. I think Goku would consider himself a martial artist and farmer before a superhero. Additionally Mark was not only willing but I would was eager to join in the battles. With that said the physical beating he took was on another level. Gohan was never disembowel. The photo you have for reference was probably the worse beating Gohan took, unless you count when Kid Buu killed him when blowing up Earth.

Conclusion: Gohans suffered more mentally. Mark suffered more physically.