are the Conan stories actually good?

Yeah, they are. Don't expect high literature, but they're good pulp fun and from time to time have little touches that elevate them above the run of the mill. I really like "The Tower of the Elephant", for example.

Conan is a barbarian hero who is tougher than anyone else in the entire world, and he makes his way from being a raw youth fresh down from Cimmeria who becomes a petty criminal in the 'civilised' cities (and isn't too impressed by civilisation as such, but likes the money, women, and booze) to eventually, via a lot of adventures, becoming king of his own realm.