I think, perhaps, we suffer an embarrassment of riches. When C.S. Lewis was awed by this work, there was no LotR, no Narnia Chronicles, no Star Wars, no Harry Potter, no Foundation Series, et cetera.
Phantastes now strikes me as heaps of Victorian: cluttered, close, stuffy even, in places. There's a fresh, clean air that blows through Fairy in SMOW, by contrast, that just isn't there in Fairy of Phantastes.
Just by way of slight biographical commentary, by the time one gets to the "four doors" section, one has a clear sense that George MacDonald had "mother" issues. Anodos "crashes and burns" in between mothering figures. It is said that Tolkien idealized his own mother, who is understood to have had a very strong influence on him being Catholic, which is no doubt accurate; and we have Elbereth and Galadriel, and perhaps Miriel, to show for it; however, they are much more subdued in their "mothering" than the various matrons in Phantastes, which is at times downright mammarian.
