I've had a couple dozen students working through many of the CodeCademy programs this semester as an experiment. And most of the Javascript lessons currently on the site are just barely above mediocre.
Zed Shaw, on the other hand, does a marvelous job of not covering concepts until the prerequisite knowledge is already in place.
Frequently, I just settle for "it adds quotes around strings" because the truth is a bit much to handle at that point.