Halting State is a virtual-world whodunit, centering around a virtual bank heist inside a MMORPG. The novel's structure is three intertwined second-person narratives (apparently a nod to second-person text adventure games). The three plot threads work fairly well, but the second-person viewpoint doesn't work as well as it could have -- I found at least two (and sometimes all three) of the characters basically interchangeable. It's a fun near-future romp in the fields of Charlie Stross's mind, but it's not his best book. (I feel like he took some experimental chances for this one but they didn't fully work. But good for him to be taking chances.)
Glasshouse is a seriously disturbing book (or at least I found it so). The first-person (present-tense) narrator, Robin, is a veteran of the Censorship Wars (during which the wormhole/teleporter network was hacked by seriously Bad Guys) who has had a big chunk of his memories removed surgically in an attempt to -- well, he's not sure, since he can't remember. While in a rehab environment, he joins an "experimental anthropology" study wherein he and other humans will be put inside an isolated environment and will try to recreate late-20th century culture (since by the 27th Century when the book takes place, history has been mostly blasted into oblivion).
It takes the first quarter or third of the book to get Robin into the experiment (complete with a new, female, body and a new name, "Reeve"), at which point the whole novel becomes an astonishing and stomach-churning investigation into both the social structure of a stereotypical 1950's U.S. suburb and social experiments. The investigators mix panopticon surveillance (thus the Glasshouse of the title) with social status incentive structures that make the Stasi seem like your neighborhood Girl Scouts. Some of the other participants take to the experiment like ducks to water and turn into the worst kind of people -- think high school "popular kids" raised to the Nth power. I was forcefully reminded of the Stanford Prison Experiment, and Stross even places a "Zimbardo protocol" reference in later (Philip Zimbardo ran the Stanford Prison Experiment). (Somewhat unrelated to the story, there seem to be a large sprinkling of Cordwainer Smith references in the book.)
Robin/Reeve quickly realizes that something is seriously wrong with the experiment and starts making plans to escape. I won't spoil any more of the plot, but I will say that it unfolds very effectively and concludes satisfyingly.
Bottom line: Halting State: fun, but it will date quickly like most near-future SF. Glasshouse: highly recommended unless you still have nightmares about high school social structures.