The Great Saiyaman is hilarious, it's almost like a parody of classic American superheroes.
The costume is an amalgamation of many different heroes. The silly helmet is my favorite, dude looked like a VR trooper or a Power Ranger. The green tunic, reminiscent of Link from the Legend of Zelda, the saiyan gloves and boots, the classic red Superman cape and underneath...tights, a staple in all superhero costumes.
As goofy and over the top as Gohan was it plays to this being his "alter ego" as much as Peter Parker being more smart mouthed and witty as Spider-Man, a change in personality is as useful as a change in costume.
He may have looked like a fag and a goofball but he didn't take himself too seriously, he was having fun in a mask fighting crime. Even though he was older, he was still a kid in a sense as he was only in his teens.