I've mostly read Murray Leinster's short fiction, and enjoyed it. This was my first voyage into his (sort of) longer fiction, and I'm glad it wasn't my first encounter. This is as pulp as pulp can get, but not in a good way.
Leinster seems to have revisited this series several times, restructuring with each addition. I first came to this via "Mad Planet", a novella first published in Argosy in 1920. I found it interesting, but rough going. Lots of repetition, some continuity errors, and overall on the dull side. The story seems to have been followed by "The Red Dust" and "Nightmare Planet", with changes each time. I skipped instead to The Forgotten Planet - a novelized version of the series. Between Mad and Forgotten, the action has moved from Earth to another planet - not greatly important, but I liked the change. Where Mad ended rather abruptly and without much resolution, Forgotten ties everything up very carefully.
Overall, in either version, this is a somewhat standard 'man becomes tiny'-type story - lots of battling with giant ants, beetles, spiders, etc. It's mildly interesting, but it's also very much on the gruesome side - lots of details of cold-hearted killing and eating alive. Let's just say that I've liked Murray Leinster, but not because of this story, and I'm glad I didn't start with him here.