I have been reading these two novels in successive order, and found the comparison to be quite interesting. I will share my wisdom here, but it should be taken with a grain of salt as my tastes in books are quite narrow (some might say I mostly read shit).
First of all, what with the “geek cred” title ? On one side, we have a book by Mark Russinovich, who is widely known is the IT security world for his contribution to the understanding of the Windows kernel : Windows Internals. This book had been a lifesaver at a time where he was not working with Microsoft and this book was not edited by Microsoft Press. During this dark age, this was the best reference to the workings of the most popular operating system in the world, and was of interest to enlightened sysadmins and reversers alike. He also authored quite a few tools (the Sysinternals tools) that helped tons of pentesters working without crashing customers servers. This man does know what he is talking about, and plays this card in this book. This is a techno-thriller that depicts a “realistic” picture of what we could expect from the future when we talk about cyber warfare.
On the other side of the ring, we have Charles Stross. I do not know much about him and only read Accelerando, which I found was pretty bad. On the other hand, this man knows his Internet subculture and obviously a bit about how it works (the title alone is a strong hint). In this book he is clearly chasing on the same fields as shows like the Big Bang Theory or Breaking In.
Both books have huge appeal to me, have similar plots (groups of bad guys wreaking havoc the digital facilities we depend so much on), but really distinct styles. What I found interesting was the cast. Zero Day features an expert reverse engineer specialized in malware and his female counterpart. Both are incredibly good looking : one of them looks like a rugby player, and the other avoids relationships because her boyfriends idolize her for a beauty (WTF?). Halting State has several main characters, but I am going to focus on the related pair : a no-life software engineer with a bit of fat, and a quirky librarian looking woman. Even though Zero Day features IDA listings, plausible technical stuff and Russian hackers, it is about as realistic as a Tom Clancy novel: the cast of Hollywood style American heroes and evil terrorists is shallow. Of course I have been reading Clancy’s book until I got disgusted with it (I am slow to realize when something went bad, so I only stopped at Net Force 1), so I am strongly biased.
On the other hand I liked Halting State quite a bit. It even included “ORLY?” in the dialogs, and a pretty interesting economic scheme about MMOs and ARGs. I can not pass the pleasure to quote a part of the book I liked a lot (select the following text if you want to read it, it might spoil quite a bit):
They are a gaming clan, and by all evidence a fucking hot one, and they’ve got the technical backup from hell. The Chinese gamers, they’re vicious. […] They’re going to grief us hard […]
If you ever played an online game against a bunch of teenagers, you will feel this story to be quite realistic.