Actually, I won't admit this very often, but the musical book doesn't stick as closely to the playtext as I thought it did. I've been rereading it, and am planning on doing a thorough reread immediately before seeing it again at the Novello.
With one real exception and one about equal, the London cast are running rings around the original Broadway cast, so I do recommend
Spring Awakening if you think you can. Check the matinee time though! It was 1.30pm when I went, and I very nearly didn't talk my way out of work early enough. O_O