The Demigod is, as you can imagine, the child of a mortal and a god, your typical Hercules or whatnot. The race has a "Divine" origin (see the post above, though), radiant resistance and mainly express their parentage by having a Divinity feat as a racial feature. The story fluff accompanying the crunch is adequate, presenting the idea of demigods as outsiders with varying degrees of acceptance according to where they live. There's 5 new feats, and a full entry for demigod monsters (4 varieties, lore and encounter groups) rounding it all out.
Where I was a bit disappointed was in the feats section, not because the ones presented aren't good (they're fine), but because this would have been a great place to add feats that customize each demigod to be a better representation of the parent deity, a place to make the race truly unique. An obvious example: even though the image used in the product has wings, there's no way for your PC demigod to have wings and hover/fly.
The product comes bundled with a number of helpful forms, including sheets of empty power cards (though the encounter feat power presented in the product does not come pre-filled into one of them) and a character sheet, and token sheets featuring the cover art in Medium and Large size. They are a fine addition, if unrelated to the actual product (save for the tokens).
Overall, it's a pretty good value. Lee did a fine job here of presenting this race (though I'd like to suggest that Lee Hammock's name be added somewhere in the product), and it certainly fits the 4e ethos of non-Tolkienesque fantasy.