So, "Fear Her" has this reputation for being the worst episode of the new Doctor Who series. I decided to give it another look recently, just to see what inspired all the hate. And really, I just don't get it. It's a fairly forgettable episode, all told, and ultimately it's trying to accomplish the same thing that "Vincent and the Doctor" did: tell a moving, down-to-Earth story about a character in emotional turmoil, and somehow involve a massive alien threat. In that regard, "Vincent and the Doctor" is clearly the better episode, even if the alien threat never feels as necessary to the story as the one in "Fear Her."
The story is...weird. The "alien who just wants to be loved" plot feels like it would fit better in "Sarah Jane Adventures," while the "little girl wishes people to the cornfield and brings her abusive father back from the dead" angle would almost fit in better with "Torchwood." All that combines to give a very schizophrenic story, which never seems to be able to decide what mood it has, and ends with the people of the world sending their love energy to power an alien spaceship.
But the worst episode of the series? Worse than "The Idiot's Lantern" or the "Daleks in Manhattan" two-parter? I've always thought that the only real value in "New Earth" or "Gridlock" was the Face of Boe stuff (but I haven't watched "Gridlock" in awhile). I don't get why the excesses and bad ideas of "Fear Her" trump basically the same bad ideas (and without the attempt at emotional grounding/fright) in "The Idiot's Lantern." Why does this episode get all the fanhate?
On the other hand, "Love and Monsters" is one of my favorite episodes, so your mileage may vary.