I love the concept of these little mini-adventures. Individually, they are worth the $1.50 or so that each of them costs. Even if you don't use the Hero system (which I don't), they're nice, concise plots, each with a very "pulpy" feel. Taken together, they can make the basis for a great, long-lasting campaign, especially with the inclusion of the "Inner Earth" material. The artwork and maps are much improved in the combined volume, and definitely worth the price.
[4 of 5 Stars!]