I did quite enjoy this one. Maybe three and a half stars?
Ryder Hook is involved with some shady smuggling stuff that brings him to Star City.... uh... Stelopolis maybe?
While there he gets caught up in the wealthy 'luxury' class who think it is fun to hunt the primitive though sentient individuals living on the planet below. Hook gets angry and ends up getting marooned on the planet and doing his best to save the swamp clans from the attentions of the Star Men. There is a lot of action, more interesting concepts and world building than one realises, while reading. Actually a lot for such a thin book. I especially liked the idea of a city in flight, orbiting any world it feels like having been forced to leave it's doomed planet. Very much like Cities in Flight Vol. 1 by James Blish.
Not sure that the author did a spectacular job of convincing up this city was the be all and end all of luxury, but there was a pretty interesting overall plot for a serial novel. It is very much pulp, as is it's cover. About the cover; cover art by Peter Goodfellow does not do credit to the artist, but then the book probably does not do credit to the author either so they might be a good/bad pulp match. Goodfellow did a lot of classic sci-fi cover art, most of which was a lot better than this, in the 80's he became a landscape artist and a fine one at that.
I collect Ken Bulmer's stuff but this is not one of his best, to me. I know others who like this series quite a bit but I much prefer his fantasy work to his space opera. It's a quick and easy read and I certainly did enjoy it. But I like his Dray Prescot series much better.