Oh, there is their metaplot, then there is my metaplot.
Their metaplot (apart from the 3-4 books they published, which I haven't read) basically consists of where the world is at right now: the lands' struggle to heal it self, the Gods and their followers struggle to maintain dominance in the world, the Titans' followers attempts to revive them, Virduk and Calastia's expansion, etc. There are some suggested plotlines, but nothing of the scale of say, sa PegInc plot point setting. There is a lot of room, though, and a lot of avenues you could go down and develop in pretty much whatever kind of direction you wanted to.
There is a series of modules (the Amphora modules) specifically for the Scarred Lands, and I would call them fair to good. With a little additional fleshing out, you could make them a good centerpoint to a campaign. With a lot of fleshing and expanding, you could make it the point of the whole campaign.
For my game, I'm planning on taking a lot of "what is known" (ie, what is published) and flipping it on its ear. Of course, the players won't know that initially, or perhaps ever.
Edit: The Ghelspad Campaign Setting and Ghelspad Gazeteer are the primary setting books. There is also a Termana book and gazeteer; it is another continent (south of Ghelspad, within sailing distance) and is not necessary - but the Termana guide has some really interesting ideas in it.
