The key feature, to me, of the first two volumes of Gibson's Sprawl trilogy is the Sprawl itself. The BAMA--Boston-Atlanta Metropolitan Area--is the urban environment taken to ridiculous extremes. Like any large city, it contains both rich and poor and those in between (like New York, it radically exaggerates the difference, although the truly rich don't even need to share a planet with everyone else in Gibson's world). Molly--who has "gone Chiba"--is the ultimate predator in this new urban jungle; in the short story, "Johnny Mnemonic," Molly takes down a heavily cyborged Yakuza assassin for what basically amounts to kicks.
But this is a a strangely anonymous urban jungle (as Molly is a strangely anonymous character; featured in two novels and a short story, we never really see what makes her tick--just as her mirrorshades, one of the truly memorable symbols in the book, have replaced her eyes, the surface may be all that there is). There are no landmarks, except that provided by a few long-time residents; there is no history to be discovered in the Sprawl. The Count's complaints about Barrytown in Count Zero are chosen (deliberatly, one assumes) to strip out any sense of the specific. When Case, Molly, and their whole wild bunch jet off to Istanbul, there's no sense that they've exited one culture and arrived in another. Only the graffiti changes.
This seems to be the end result of the Sprawl. A nation of low-level hustlers, completely disassociated from the past and the future, stuck in a city with indeterminate borders, indistinguishable from any other. Science fiction determined not by Mitchell's Cambridge and Silicon Valley but by Bed-Stuy and Watts and a thousand undifferentiated edge cities.