I think Children of
Hurin is more approachable, although I find it hard to be sure I'm right about that, since I knew the story so well before I even picked it up. I think as a standalone novel it is actually quite flawed, since its approach to giving you the immense backstory is incredibly clunky. Compare, for example, the marvellously artful way that JRRT introduces it in Lord of the Rings.
By contrast
the Silmarillion is the backstory. It is without doubt a more
difficult work, but when it gets going (and get used to the fact it isn't a conventional novel), its is very moving and I think it reaches heights that CoH does not, through its sheer scope.
My problem with Children of Hurin is that it doesn't seem to be one thing or the other. Neither the lofty remoteness of Silmarillion, nor the intimate story-telling of Lord of the Rings. Clearly a problem for Christopher
Tolkien to do any more, within the confines of the material available to him - and he should be thanked for publishing the story in a final form. I feel fairly sure that JRRT would have not been satisfied with this story - indeed, if he had been, he would have probably published it himself.
That, though is obviously true of the Silmarillion too!