As a child, I greatly preferred the original. A lot of the emotional subtext from the sequels went over my head (since I was raised in a very emotionally repressed environment), but I could totally grok the cold, somewhat impersonal nature of the first book. It was easier to imagine myself in this huge alien structure when I could understand the characters. Nowadays I think I'd probably prefer the sequels since I derive a lot of enjoyment from interpersonal drama and conflict. I'll admit that it's been ages since I've read them, so I can't say for sure.