Of the three stories this issue–the first two are original, the third is a sixties reprint–Man-Thing is the easy winner. The other two aren't any competition.
The reprint is a Stan Lee and Larry Lieber (probably) written tale of greed. Don Heck gets some moody art in, but nothing particularly good. The writing's lame.
Ditto for the second story, which is sort of a tale of greed. Bugsy Malone versus pirates. Allyn Brodsky's script is terrible. Jack Katz and Bill Everett contribute indistinct art.
But as for Man-Thing… the art, from Howard Chaykin and Gray Morrow, is pretty good. And Gerry Conway's script has a couple moments. Not enough, but a couple. The problem seems to be his pacing. He front loads the story setting up Man-Thing and then doesn't have enough room for a good finish. It's creepier with the bad finish… maybe Conway intended that reading of it.
Man-Thing; writer, Gerry Conway; penciller, Howard Chaykin; inker, Gray Morrow. The Spell of the Sea Witch; writer, Allyn Brodsky; penciller, Jack Katz; inker, Bill Everett. There Is Something Strange About Mister Jones; writers, Stan Lee and Larry Lieber; artist, Don Heck. Letterer, Artie Simek; editor, Roy Thomas; publisher, Marvel Comics.