I'd recommend the book to anyone, even if only for its historical value as one of the lasting early[1] self-help books (together with Napoleon Hill's, I guess). There are some good insights in the book that are worth following.

However, it shares some of the problems that many modern self-help books have as well: very high on anecdote and broad generalizations, yet very light on evidence, or even considering alternative explanations for observations.

[1] Of course, self-help books are as least as old as Marcus Aurelius' Meditations...