I know this is a bit late (this thread has been dead for years), but for anyone interested: I prefer the longer and admittedly more rambling narrative found in HoME (the History of Middle Earth series) to that collected in "The Children of Hurin," for one reason: CoH is too short. Most people don't know (or care?) that Tolkien carried this story way past Morwen's death, writing a very powerful narrative of Hurin in Brethil, Nargothrond, and Doriath--and even past Hurin's death, the war of the Valar and the Dagor Dagorath ("Battle of Battles") at the end of the world. That's where this story should end, but I suppose it was too tough to come up with a way to connect the narrative together at all points. *sigh*
The good thing about CoH is that it's consistent and collected together all of a piece--before, if you wanted to read the full story, you needed six or seven books; now you only need 3 (4 if you're a completist): CoH, the Silmarillion, and The War of the Jewels (The Book of Lost Tales contains prophecies about Dagor Dagorath). I'm also glad that the story is out there independently--it deserves to be (and so does "Beren and Luthien," probably), though the story itself isn't for everyone.