On a scale of solely literary books, maybe a 3/5. But it's hard to rate anything CM wrote below about a 4/5 due to writing strength alone. 

McCarthy's first published novel, it has all the aspects of his later writing, but congealed with an extra coating of thickness in the prose that his subsequent books would shed.

His later books feature an economy of prose without reaching Hemingway levels of sparse, and that's missed a little bit here. The writing is still gorgeous, powerful, but the richness gets a little cloying at times. Thick and chewy; some days a single page was all my senses could take. Bring a dictionary. 

The Faulkner influences are very clear here, but to call it an imitation (as some critics did when it was published) is unfair. Faulkner's characters were allegorical stand ins for various traits of the American south, whereas here CM's characters feel more like actual people unwittingly playing out a Biblical morality tale. There's definitely more modernist styling here than his other work though. 

When it comes to modern classics, there's a spectrum between "books you can read and simply enjoy" and "books you need to be actively engaging with the themes to get much out of," and this one is closer to the analysis required side. The Road can be simply read; The Orchard Keeper however has a fairly thin plot that almost doesn't make sense unless you're mentally referencing the themes. Just be warned there.

My main criticism is simply that it feels too much like a MFA thesis project, with powerful and clear themes, but less of a focus on also making a good yarn. He became a master of doing just that as time went by. But this one suffers ever so slightly from a thematic heavy handedness.