Read the book for the first time last year. I heard from some people that it hadn't aged too well—that it should be viewed as more of a precursor to things like Snowcrash —but I really loved it. In particular, the language used to describe drug states and events in cyberspace (such as the Kuang virus) was just so vivid and disorienting. (Or I guess "hypnagogic", to use a Gibsonian word.) A less talented author would…
I think Neuromancer aged better than a lot of sci fi. Gibson didn't go into technical details, which is a blessing when you deal with early 80s computer tech. Incidentally a lot of cyberpunk feels off in 2018. Nobody seemed to forecast the rise of China.
China features prominently in The Diamond Age as a location, but not as a powerful, cohesive, oppressive, incredibly successful authoritarian government. It's sort of a laughing stock in Snow Crash, and barely present in Neuromancer.
Despite its reputation for being darkly cynical, I think we can look back now and see that cyberpunk as a genre was essentially optimistic about the power of computing technology--optimistic that it would indeed radically change power structures, society, and our relationship with governments.
Instead what we see today is not that different from this time 100 years ago: super rich oligarchs controlling much of the economy, rising racism and bigotry, authoritarians using new technologies to seize power and splinter their opposition.