Conan and his world are really, really cool.
Not in a flashy "to teh extreme!!!1" fashion, but in an honest, gritty, authentic kind of way. You can tell that Howard was working with some pretty primal material here, stuff that hadn't been mined before in this way. There are prototypes by the bushel here. Yet as the book notes, this isn't the polite and haughty fantasy of Tolkien and those in his evidently long shadow. Its pulp. Its got dirt under its nails and a lust for life that is vivid in its intensity.
More than that, the world we're presented with is human-centric in outlook. Harshly so to be sure, dark at its extremes, yes, sinisterly mystical even - but its centered on people, good bad and indifferent. They're the ones who call the shots and make kingdoms rise or fall - not omniscient spirits, demons, or angelic fairies.
To take the college jargon further, I'd say its downright Existentialistic. Here we have a world where a barbarian child in a harsh, bloody world can grow up to be a rogue, a pirate, and a king - not because he is divinely predestined to be those things, but because he felt like it. Guts, brains, and balls of brass are paramount - kissing some deity's ass or having a magic stick or pointy ears isn't. Again; traits of the pulp adventure I've always had an affection for - my first RPG was the Indiana Jones game from TSR, for cri-yi.
And this isn't just Howard's writing and setting appealing to me - though I'm certainly more interested in him after reading the game. No. The system plays right into the feel of his work and the themes playing in the background. How can you not like a game system where "Pantherish Twist" is on your character sheet? Or where you can heal damage by getting a flagon of wine? And, surprise, surprise; there are no apologies made for the rampant stereotypes from the different cultures of Hyboria - in fact, they're codified into the racial benefits and penalties.
I cannot express how refreshing this is to see in a genre that seems obsessed with being something other than human and collecting toys. I get this world on a level I can't even say Exalted grabbed me. It is, to sum up, the kind of fantasy I can dig.