I seem to have overlooked this thread all these years.
I own
CoH and
Gondolin, but confess I haven't even read
Luthien.
CoH struck me as really nothing but an amalgam of the
Unfinished Tales Narn and the chapter in
The Silmarillion. As you said, it does have its moments, but I honestly could have done without it.
I'm not very keen on
Gondolin. I have always loved the
UT section on Tuor and his journey to Turgon, so a look at earlier conceptions left me a bit nonplussed.
The appearance of Ulmo to Tuor at Vinyamar is
epic. The image of a more easygoing, more kindly Lord of Waters sitting in a bunch of reeds playing with shells in order to persuade Tuor reminds me somehow of Bombadil skulking along the Withywindle. Hey! You don't suppose....