Upvoted not just for the insightful and non-snarky review, but because Greg Egan is a) the best science-fiction writer most people have never heard of - it's practically impossible to find his work in a US bookstore - and b) an interesting writer on both science and code.
Egan is one of those SF writers who lend unfortunate credibility to the notion that the genre is about ideas, not people. The depth of his characters leaves much to be desired, as does his ability to tell a compelling story. However, he's to be admired for turning out original work in a field so drenched in clichéd, repetitive bullshit.
It varies. He can be a bit plodding sometimes, especially when exploring politics - his characters tend to be introspective rather than bold actors. So I found Teranesia (SE Asian ecopolitics) rather a struggle, but on the other hand I flew through Diaspora, where most of the characters don't even have physical bodies and there were a lot of very abstract concepts.
None of his output is light reading, but (IMHO) it's extremely substantive, as opposed to the physically substantial 1,000 page doorstops and franchise vehicles...I doubt I'd enjoy a novelization of Avatar, for example. I'm into that movie for the magic carpet ride rather than the dialog or character development.
He's actually my favorite author, but yeah, when it comes to the actual wordsmithing, he's no Gene Wolfe. The ideas are always great, though, and stories usually are.
I liked Quarantine. The only Egan novel I thought a complete waste of time was Teranesia. But I'd recommend one of the three I listed first to see if he's for you.
Permutation city.
After-death scenarios, AIs, a world were computing resources are acquired by trading (even better than the futures on amazon spot instance price than someone was suggesting a few days ago :)) ,etc...
Science: http://www.gregegan.net/FOUNDATIONS/index.html Java Applets: http://www.gregegan.net/APPLETS/Applets.html