Horace and Pete is a startling creation, and a worthwhile discovery for anyone interested in good story telling, effective containment, and genre reinvention.
I think it molds the "TV format" to fit a very different type of story. Hour long episodes. An odd, recurring intermission. Not to mention a very specific mode of distribution, you can purchase it through C.K.'s website (that then branches out elsewhere).
Beyond that, it changes the usual formula employed by dramedies. Specifically, it ditches the indie tones of almost any similar story you've heard about at Sundance, or on Showtime, etc. Instead, H&P plunges you in a strange sort of earthy depression. Real, unaware sadness that seems to self-perpetuate among its characters. There's nothing starry, winking, or stylized about it.
The "comedy" that comes out of this environment is hard earned, desperate enough that it you laugh hard because you feel - just like these characters - that it may be the only chance you have to laugh and it'd be a shame to wait for a well-crafted zinger in its stead.
I don't want to summarize or generalize or spoil any further. Louis C.K. worked really hard to release the show in such a way that maximizes accessibility while minimizing hype, or marketed expectations. He says as much on his website. I recommend you go there and check it out!
If you don't want the heavy experience, you can still enjoy Paul Simon's beautiful theme song for Horace & Pete.