I used to avoid these anthology comics like the plague. I wanted longer stories about my favorite heroes and less of this "short story" style of presentation. But, even though I would probably never have purchased a copy of a single character title for Magno, Vulcan, Q-13, and Sky Smith, I found that this mix was just right. The artwork seems rather crude, especially faces of the supporting characters, but I found this to be a delightful buffet of nascent comic heroes.
Link to the book:
Super-Mystery Comics v1 01