This has long been one of my favorite books. It is a serious, no-simple-answers coming-of-age tale, yet at the same time it manages to imaginative and entertaining, with plenty of laughs and vivid imagery. Thus the story is enjoyable whether the reader is in a contemplative mood or simply craving a good science fiction yarn.
Most of all, I admire the author's use of language and dialect. He creates a form of modified English by incorporating words from several different languages throughout the text, as well as some made-up slang and terminology. (The novel is written in first-person, thus the use of dialect is constant through the text.) This can be daunting at first, but by the time you're a few chapters in you'll have 'picked up' the language to a remarkable degree. Years after my last reading, I still remember it.
Again, one of my favorites. I'm going to buy another copy soon, before my old, often-reviewed copy falls apart completely.