Oh! I forgot to add 10th Kindgom to the list of successes.

Most of the failures for me have been less strictly portal fantasy and more portal-ish treading towards urban fantasy. I think with a lot of portal fantasies it's possible to see fail coming pretty early—because, ideally, the portal is discovered early, and the hokiness/excessive ease/Mary Sues are visible from the beginning. (And then I stop reading and push them from my memory, so it's hard to list.)