From where I'm sitting, dense jargon and (expected, since it was of the time) misogyny and homophobia layered on top of a fairly interesting story. The writing was interesting, and I enjoyed aspects of Marlowe's character. The plot itself had a turn or two more than I required, and more than enough coincidences, but I guess that's just the way; no different than Sherlock Holmes or Rebus or an Agatha Christie in that regard. (I may be simplifying—I'm a tourist in these genres.)
Glad to have read it, but I don't feel a need to seek out more.