This is just a Starter Set so it's obviously not as comprehensive. The core set will be coming later, with a rulebook, a GM handbook, a land management book, and three books for the updated Great Pendragon Campaign (starting in the year 510 with the Boy King Period rather than in 485 with the Uther Period as in the original GPC).

The rulebook presented here is streamlined compared to the core 5.2e rulebook, but with a lot of the most significant updated rules from 5.2e (such as how criticals work, how Inspiration works, etc.). The campaign book only goes through a few years compared to the GPC's 85 year campaign, but it goes through the years covered with far greater detail than in the GPC (which makes sense, as the GPC is a document covering 80 years of story while this is a short introductory campaign). The 5.2e core rulebook contains almost no adventures/campaigns, so you do need to make a separate purchase of the GPC, whereas the Starter Set comes with a rulebook and a set of adventures together....See more

Basically, this is an introductory set, for people who want to try out Pendragon, worth a couple months of play at most; 5.2e and the GPC together are a full game that can last years of play. Personally, if you're not familiar with Pendragon, and you want to jump into a full-length campaign, I'd wait for the core 6e books to come out, but if you just want to try out Pendragon, this is an AMAZING resource. Even as a veteran of Pendragon I'm enjoying the hell out of this.