I don't watch enough musicals to be a credible critic but I have an idea on what makes a good one. Musicals I don't quite enjoy have a common hallmark; they're not particularly boring (Mary Poppins, for instance, has spectacular visual effects and Lion King has amazing props); what they lack is energy.
We Will Rock You (free stall tickets courtesy of Princess Dania), shines in that aspect with its high level of contagious enthusiasm. Forgettable storyline aside, We Will Rock You has great crowd interaction and an amazing selection of songs. And it's oh so funny! That, my friend, is what makes a good musical. Now, repeat after me: A funny musical is a good musical!