I read St Claire's and Mallory Towers avidly as a kid, mostly for the midnight feasts and outdoor swimming pool envy - but even then, I remember thinking the "heros" could be awful petty bitches and there was some class snobbery going on. As a younger kid I loved the Magic Tree books as well. I think they're fine for kids of a certain age and they will move on to something more interesting soon enough - isn't repetition of vocabulary useful in learning - one of the reasons small children like stories over and over - up to a certain point too?