The late and lamented Karl Edward Wagner, who wrote this pastiche, was the first to say that nobody could write like Robert E Howard but Howard Himself. Paradoxically enough, this came from the man who was best qualified to imitate the first and Greatest master of Sword and Sorcery.
This homage has some very good points, the compact, efficient prose with the right word where it is needed, and the often grim atmosphere, the violent and graphic action, natural and not so natural horrors and monsters, horror from indescribable gulf of space and antiquity... these are all elements found in the original stories, and very well rendered by Wagner.
However, Wagner, perhaps trying to outdo the Master, has committed a series of bad mistakes that detract from the book's value as a Conan yarn : First, and to my point of view worst, is getting Conan to a very high post and so close to getting a throne : if such an episode were to be added to his biography, then some of the stories set by Howard after he seizes the throne of Aquilonia would have turned differently, because he would have known of the price of power. Then, there is a problem with atmosphere: Howard's tales are characterized as very grim, this one has far too much humor, even verging on the comic... last, but not least is the fact that in this book, women are treated in a way that could never have happened in a Howard yarn: yes, he was a male chauvinist, (though beware such of his characters as Valeria, BÍlit or Red Sonya), yes his tales are written by the conventions of his times, which no longer apply, still I believe that pastiches should respect some of the original's specifications...
All being said, No, this is not quite the equal of the dark page turners Howard extracted from his tormented mind, but Yes Wagner has still produced a decent story that will please fans of the genre (or of the character) more than the general public, but for those who like a solid adventure yarn, this is your stuff, get it while you can.