Boiled down to its essence, Accelerando is a novel tracing four generations of the Macx family into the Singularity and out the other end into the posthuman future. Along the way, drastic changes occur in human society as the result of widespread nanotechnology and the continued effects of Moore's Law. Aliens are encountered, the Galactic Internet is discovered, and a lot of other weird stuff happens, including the dismantling of the inner four planets, much of the asteroid belt, and the creation of huge numbers of people based on literary descriptions - with the result that they have conspicuous holes in their memories.
Anyway, in contrast to the other Stross novels set in a post-Singularity future (Singularity Sky and Iron Sunrise) this one did nothing for me. In a lot of ways it reminds me of the old Doc Smith novels where the heroes would be chucking planets around and doing other stupefying deeds of super-science (or, perhaps more accurately, engineering on a Galactic scale) but all the characters would be made of the most ragged, overused stock cardboard. None of the Macx family really have much in the way of a real personality; they're little more than job descriptions with some occasional fetishes and stylings pasted on so you can tell the socially conservative dominatrix IRS auditor grandma from her rebellious pioneer posthuman daughter. I honestly couldn't bring myself to care about any of them, especially the cat, although I have to admit I found Manfred, the "venture altruist" protagonist of "Lobsters", spacey and annoying. Which is about as much feeling as I could summon up for any of the characters, although I did find the imam's plight somewhat interesting as he tried to deal with what appeared to be (and yet surely was not) Islamic heaven. Basically, I stuck with the novel to find out what was going to happen, being teased along by an occasional well-written chapter, and finished the thing thinking there's a good reason why none of the components won the Hugo. If I cared enough (and it was still early enough to do so) , I'd join the Worldcon for the express purpose of voting against it and for John Scalzi's Old Man's War, which is a much better book.
At the root of my dissatisfaction with the book is the assumption that merely because people can do the things that technology allows them to do, that they will do them, and neither law, force nor custom will suffice to stop them. This is the assumption that drives the book, and it's a little too pat for me to swallow. Your mileage may vary.
So, should you avoid the book, then? No. It's adequate brain candy, and as I've said, parts of it are well-written. It's a long way from being Stross' best work, though, and will probably be appreciated most by people who have already drunk the transhumanist Kool-Aid. I'm not one of them, obviously.