I took a tour of my schools too, and they were okay. They're pretty good if you're still just applying to schools, and can take another indepth tour of the places you're actually accepted. Mine were always pretty small, so I was able to ask as many questions as I could, which made it nice. They always showed me where the museum and the Art History Department were.
At my school, tour guides were volunteers--so you definitely got someone enthusiastic about the school, who really wanted to be giving that tour at 9 AM on a Saturday.