Greg Egan is a classic hard sf writer in the sense of spending more time on the ideas than on characters, which worked for me in Permutation City, with inevitable march of consequences for the technology it describes, and I loved it, but Quarantine I found lacking because it only really has one big idea which feels too drawn out over the whole book, which got boring for me.
Btw, have you read Accelerando by Charlie Stross? The actual writing and story could use some work, but it almost doesn't matter because it has the most ridiculously high idea ratio of any book I've read. It's like every word of every sentence has five new ideas in it somehow. :)