The material in an average issue of MU was varied, but interesting: there would usually be a Man-Thing story, a handful of generic, newly-created horror tales, some precode horror reprints, and even articles about monster movies and television shows. The comics were the dominant part of the magazine, but overall the feeling one got after reading an issue was that it was more or less a complete monster-fan experience. Apparently it was another attempt by Marvel to compete with Jim Warren's offerings, but it works. Although few of the stories could be called outstanding, the overall quality of the comics is actually pretty good.
Monsters Unleashed lasted ten issues, with one annual.
For a cover gallery of Monsters Unleashed issues, try here.