I've seen Phantom a couple of times. It has a good pedigree. Lyrics by the then unknown Charles Hart, who seems to be using a number of Sondheim-isms in his writing (as does ALW in some of the dialogue scenes IMHO), and direction by Hal Prince, who is behind a lot of famous musicals (including Evita and quite a lot of Sondheim works). The stage machinery alone is worthy of note, but the sheer drama of the piece is just magical. You have everything from pathos to blood-curdling screams and murder... with the obligatory love story. I've read a piece saying that it is cheesy to try to get the audience to sympathise with the villain, but what the hell - everything's possible in showbusiness!