The opening chapter of Lady of Mazes by Karl Schroeder is mind-boggling. Not that the rest of book is less so, but that first hit was so unexpected that I was really in a shock. I had to adapt, wrap my mind around the new “reality”, all the new ideas and their implications. And that kind of stuff kept coming at me, page after page, but having experienced that first wave, I’ve braced myself and started enjoying it. 
And there’s plenty to enjoy if you’re an SF fan. Because this is hard science fiction at its best. The concept of `Societies` is an excellently extrapolated vision of the social interactions we’re having on the net today. Same goes for the `Inscape` and the `Manifolds` – the idea that your location and actions in the “real” world are almost of no significance and that it’s all about the “virtual” world, takes some time to get used to.
I don’t like too much action in any novel, and this one has just about the right amount of it (e.g. Consider Phlebas by Iain M. Banks has a bit too much for my taste and The Player of Games by the same author is spot on), but you won’t even notice it while you’re reading as the world and the story are overwhelming. There are moments when you realize that a common word does not have the same meaning any more, as the circumstances are quite different from the real world and realizing it only pulls you deeper into this imagined world.
Having said all that, it shouldn’t be surprising that I’ve already downloaded the free Ventus novel from the author’s official site and as I haven’t read Sun of Suns either (downloaded from Tor.com last year), I expect to be having great time submerged into the distant future.
