For all the people saying Cyberpunk has an inherent dystopian vibe: Not necessarily true. Much of what cyberpunk focuses on aren't social strata, or the emergence of Orwellian police states, but rather the human condition and the ever shrinking divide between man and machine. To put it more simply, how human is Human? A lot of William Gibson's novels dealt primarily with this question, with AI that ranged from pop singers and humble servitors to metaphyisical gods, and humans filling in everywhere in between while coming to grips with the fact that their tools had become "people" themselves.
Other stories deal with issues like human inter-dependency and individualism in a world where everyone can be connected with each other at all times (i.e. The Internet), or learning in teaching in an age where the "teacher" is unnecessary. All very high-concept stuff, all possible due to a futuristic setting that still feels familiar.
Steampunk, on the other hand, is all setting. Its an almost inherently fantasy world, that focuses primarily on historical revisionism but is so obsessed with maintaining the same few concepts for stylistic reasons that it refuses to move out of its comfort zone. Its a world that seems bound and determined to remain in the trappings of the same 100 years of history, evolving the technology of the era but refusing the truly innovate. Yes yes, clockwork robots and Star Destroyer-sized blimps are amusing, but it feels so gimmicky that its hard to take seriously. Why not branch out? Maybe do a Steampunk Renaissance setting, with clockwork Da Vinci machines and a spray painting Rembrandt? Or hell, go back further and have the Crusades fought with steampowered tanks and clanky powered armor? But they never will, because those "aren't steampunk". Looking at most of the posts we've seen so far, most people when they think of Steampunk think "Victorian clothes and Abe Lincoln with chaingun arm". Its a setting that simply refuses to move on and try new things, and I'm afraid its stagnating for it.
TLDR, Cyberpunk focuses on concepts, Steampunk focuses on its setting. Cyberpunk, IMO, is the stronger genre for it.